Semantic Web Research Overview
August 2005-August 2007
Project Overview
The Semantic Web research for intelligent sensors was conducted under the supervision of Dr. David J. Russomanno at The University of Memphis Department of Electrical and Computer Engineeringwith the Center for Advanced Sensors.
The topic that I investigated during my research was the following: Given a network of thousands of wired and wireless heterogeneous sensors, how can the sensors be discovered and dynamically utilized for applications that might not have been anticipated on initial deployment? I inherited the work-in-progress ontology called OntoSensor which is a knowledge model describing sensor properties. A laboratory test bed was created using wireless sensors that referenced OntoSensor.
The next phase of my research can be summarized as a search engine leveraging a service-oriented architecture that utilizes an ontology instead of statistical methodology to discover live sensor services. The architecture leveraged the Universal Description Discovery and Integration (UDDI), which is a industry standard syntax-based search registry for Web services. The developed architecture is composed of two primary modules: i) UDDI and ii) semantic sensor matchmaker. The semantic sensor matchmaker works in conjunction with UDDI to discover sensor services using semantic processing. Ontological knowledge pertinent to the satisfying a query is updated/inserted into the UDDI database. The process is analogous to using a set of compiled heuristics first (that is, the explicit facts in the UDDI database) then falling back on deeper knowledge (the sensor ontology) if the heuristics do not provide an acceptable solution. The research work resulted in one conference paper which I presented at the 2007 International Conference on Semantic Web and Web Services.
Sensor Ontology
Project Overview
OntoSensor is a Semantic Web compatible ontology developed using Protege. OntoSensor references and extends the IEEE Suggested Upper Merged Ontology (SUMO), which defines general concepts and associations. OntoSensor is based in-part upon SensorML, which defines associations and properties common to sensors. OntoSensor deviates from SensorML since it lacks the semantic richness, such as axiomatic-grounded terms, which may be required for automated data fusion and inference in a distributed sensing environment.
Ontology-Based Sensor Network Prototype
Project Overview
The ontology-based sensor network prototype is comprised of two computers that serve as base stations and store the data collected from the MIB510 and MIB520 network gateways. The base stations register their respective services with the sensor service broker developed for my thesis and published in 1 and 2. The sensor service broker allows semantic discovery of the registered services. Each base station receives data from a sensor network. The wireless sensors form ad-hoc communication links to route the collected data back to the base station. The base stations run Crossbows MoteView application to retrieve data from the network gateways and the data is stored in a PostGRE database. In addition, each base station executes custom software developed for during my thesis that extracts sensor data and metadata into OWL repositories that reference OntoSensor. The software is a preliminary implementation of a Web service that is evoked at the base stations for selectively storing sensor data into OWL repositories within the networked environment.
The base stations also serve as a logical interface for tasking the individual sensors through Web services. Base stations also provide physical storage aggregation nodes for sensor data and metadata that can be used in response to queries by agents, rather than involving the individual sensor nodes in responding directly to queries.
Semantic Web Service Discovery
Project Overview
This architecture includes the Prolog implementation of a UDDI inspired repository, sensor matchmaker, and sensor service interface. The sensor matchmaker is registered in the Prolog UDDI registry and is invoked by the sensor service interface to provide semantic search capabilities. The matchmaker stores in UDDI the semantic metadata pertinent for satisfying a query so that subsequent syntactic search queries can be satisfied directly from the UDDI repository and avoid the overhead of semantic-based search. The sensor matchmaker has the following capabilities; i) search via generalization; ii) search via specialization; iii) performance property search; iv) supported applications search; and v) loading additional semantic metadata to satisfy
queries.
Relevant Publications
D.J. Russomanno and J.C. Goodwin (2008) OntoSensor: An Ontology for Sensor Network Application
Development, Deployment, and Management, Handbook of Wireless Mesh and Sensor Networking,
McGraw Hill
J.C. Goodwin (Thesis) Ontology Integration within a Service-Oriented Architecture for Sensor Networks.
J.C. Goodwin and D.J. Russomanno. (In Peer Review) Ontology Integration within a Service-Oriented
Architecture for Expert System Applications using Sensor Networks, Journal of Expert Systems
J.C. Goodwin and D.J. Russomanno. (2007) Survey of Semantic Extensions to UDDI: Implications for
Sensor Services, The 2007 International Conference on Semantic Web and Web Services
J.C. Goodwin and D.J. Russomanno. (2006, Poster) An Ontology-Based Sensor Network Prototype
Environment, Fifth International Conference on Information Processing in Sensor Networks, Nashville,
TN.
THESIS
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Ontology Integration within a Service-Oriented Architecture for Sensor Networks
This thesis describes the development and implementation of an ontology-based network
centric service-oriented architecture for discovery of sensor services using semantics.
The architecture enables software agents to discover ubiquitous sensors referencing
machine-interpretable service descriptions, such as those proposed by the Semantic Web
effort, enabling on-the-fly utilization of sensors for applications that might not have been
anticipated on initial deployment. The developed architecture overcomes some of the
limitations of the current service-oriented architecture technologies that rely solely on
XML data structures and syntax-based search mechanisms for discovery of Web services.
The architecture developed in this thesis allows for the generalization, specialization,
performance property, supported application, and instance semantic processing to satisfy
queries. Furthermore, the architecture seeks to enhance the syntactic search for sensor
services by extracting semantic metadata from a sensor ontology pertinent to satisfying a
query and saving it in the service registry.
Journal
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Ontology Integration within a Service-Oriented
Architecture for Expert System Applications using Sensor Networks
This paper describes the development of an architecture for the discovery of sensor services
leveraging ontology-based semantics in the search query. A prototype has been implemented
based upon the architecture and can be used to support the development of expert system
applications in which sensors of certain types, operational capabilities, or physical properties are
required to support applications within a network-centric environment. In the prototype, sensor
services are listed in a registry that references a machine-interpretable ontology. The registry
conforms to the Universal Discovery and Description Interface (UDDI) specification, but it is
augmented with semantic matching via an ontology to increase the likelihood that relevant
sensor services are discovered when needed by expert system applications.
Conference
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Survey of Semantic Extensions to UDDI: Implications for Sensor Services
Abstract-The ability for software agents to discover,
query, and task ubiquitous sensors requires machineinterpretable
service descriptions, such as those
proposed by the Semantic Web effort. Descriptions that
support deep semantics will enable on-the-fly utilization
of sensors for applications that might not have been
anticipated on initial deployment. Semantic Web service
discovery and dynamic composition requires formal
semantic descriptions of inputs, outputs, preconditions,
and effects of services. Universal Description
Discovery and Integration (UDDI) provides a registry
for publication and discovery of Web services, but it
lacks the semantics needed for discovery and
interoperation as envisioned by the Semantic Web
community due to UDDI’s syntax-based search. This
paper surveys representative approaches for
incorporating semantic capabilities within the existing
UDDI infrastructure and then proposes an architecture
for sensor services within an ontology-based networkcentric
environment.
Book Chapter
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OntoSensor: An Ontology for Sensor Network Application Development, Deployment, and Management
This chapter describes the potential utilization of an ontology in heterogeneous sensor network environments to facilitate discovery, query, tasking, inference, and interoperation of a myriad of sensor types. As sensor networks advance, they will no longer be dedicated to specific applications in which a priori knowledge of the sensors’ capabilities and access methods are procedural bundled within application-specific software. In dynamic scenarios, declarative knowledge sources are required to support the on-the-fly utilization of sensors by software agents. A laboratory environment and evolving sensor ontology have been constructed to experiment with such scenarios. OntoSensor has been implemented using the Web Ontology Language to model sensor properties, associations, and services providing meta data about sensor types, as well as the knowledge required for subsequent interoperability given that the sensors may contribute to an agent’s overall goal.
Poster
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Ontology-based Sensor Network Prototype Environment
Abstract—This paper describes work-in-progress development of an ontology-based, sensor network prototype environment to facilitate research in distributed, heterogeneous sensor inference, fusion, tasking and control. Currently, the prototype environment consists of wireless sensing capabilities that include temperature, acceleration, GPS, light, barometric pressure, magnetic field and acoustic measurements, with wired visible, infrared, and other high-bitrate sensors pending integration. Communication links formed by the sensors permit the aggregation of data at the base stations. Each base station includes a process that generates a sensor data repository from the raw percepts, which is marked up using the Web Ontology Language (OWL) to reference the OntoSensor ontology. Each sensor type in OntoSensor is defined using concepts, associations, and services providing meta data about each sensor, as well as requisite knowledge for interoperability and data fusion. A software agent developed in SWI PROLOG loads the OWL sensor repositories into its knowledge base for subsequent application. Currently, the agent only supports ad-hoc queries of the sensor repositories to discover trends in the measurements. Plans for future work include demonstration of proof-of-concept utility of sensor ontologies in distributed sensor processing and control.