Service Composition in a Global Service Discovery System

GloServ is a global service discovery system which aggregates information about different types of services in a globally distributed network. GloServ classifies services in an ontology and maps knowledge obtained by the ontology onto a scalable hybrid hierarchical peer-to-peer network. The network mirrors the semantic relationships of service classes and as a result, reduces the number of message hops across the global network due to the domain-specific way services are distributed. Also, since services are described in greater detail, due to the ontology representation, greater reasoning is applied when querying and registering services. In this paper, we describe an enhancement to the GloServ querying mechanism which allows GloServ servers to process and issue subqueries between servers of different classes. Thus, information about different service classes may be queried for in a single query and issued directly from the front end, creating an extensible platform for service composition. The results are then aggregated and presented to the user such that services which share an attribute are categorized together. We have built and evaluated a location-based web service discovery prototype which demonstrates the flexibility of service composition in GloServ and discuss the design and evaluation of this system. Keywords: service discovery, ontologies, OWL, CAN, peer-to-peer, web service composition

Combining Ontology Queries with Text Search in Service Discovery

We present a querying mechanism for service discovery which combines ontology queries with text search. The underlying service discovery architecture used is GloServ. GloServ uses the Web Ontology Language (OWL) to classify services in an ontology and map knowledge obtained by the ontology onto a hierarchical peer-to-peer network. Initially, an ontology-based first order predicate logic query is issued in order to route the query to the appropriate server and to obtain exact and related service data. Text search further enhances querying by allowing services to be described not only with ontology attributes, but with plain text so that users can query for them using key words. Currently, querying is limited to either simple attribute-value pair searches, ontology queries or text search. Combining ontology queries with text search enhances current service discovery mechanisms

A Hybrid Hierarchical and Peer-to-Peer Ontology-based Global Service Discovery System

Current service discovery systems fail to span across the globe and they use simple attribute-value pair or interface matching for service description and querying. We propose a global service discovery system, GloServ, that uses the description logic Web Ontology Language (OWL DL). The GloServ architecture spans both local and wide area networks. It maps knowledge obtained by the service classification ontology to a structured peer-to-peer network such as a Content Addressable Network (CAN). GloServ also performs automated and intelligent registration and querying by exploiting the logical relationships within the service ontologies

Distributed Search in Semantic Web Service Discovery

This thesis presents a framework for semantic Web Service discovery using descriptive (non-functional) service characteristics in a large-scale, multi-domain setting. The framework uses Web Ontology Language for Services (OWL-S) to design a template for describing non-functional service parameters in a way that facilitates service discovery, and presents a layered scheme for organizing ontologies used in service description. This service description scheme serves as a core for desigining the four main functions of a service directory: a template-based user interface, semantic query expansion algorithms, a two-level indexing scheme that combines Bloom filters with a Distributed Hash Table, and a distributed approach for storing service description. The service directory is, in turn, implemented as an extension of the Open Service Discovery Architecture. The search algorithms presented in this thesis are designed to maximize precision and completeness of service discovery, while the distributed design of the directory allows individual administrative domains to retain a high degree of independence and maintain access control to information about their services

Ontological Problem-Solving Framework for Assigning Sensor Systems and Algorithms to High-Level Missions

The lack of knowledge models to represent sensor systems, algorithms, and missions makes opportunistically discovering a synthesis of systems and algorithms that can satisfy high-level mission specifications impractical. A novel ontological problem-solving framework has been designed that leverages knowledge models describing sensors, algorithms, and high-level missions to facilitate automated inference of assigning systems to subtasks that may satisfy a given mission specification. To demonstrate the efficacy of the ontological problem-solving architecture, a family of persistence surveillance sensor systems and algorithms has been instantiated in a prototype environment to demonstrate the assignment of systems to subtasks of high-level missions

An Ontology Based Approach Towards A Universal Description Framework for Home Networks

Current home networks typically involve two or more machines sharing network resources. The vision for the home network has grown from a simple computer network, to every day appliances embedded with network capabilities. In this environment devices and services within the home can interoperate, regardless of protocol or platform. Network clients can discover required resources by performing network discovery over component descriptions. Common approaches to this discovery process involve simple matching of keywords or attribute/value pairings. Interest emerging from the Semantic Web community has led to ontology languages being applied to network domains, providing a logical and semantically rich approach to both describing and discovering network components. In much of the existing work within this domain, developers have focused on defining new description frameworks in isolation from existing protocol frameworks and vocabularies. This work proposes an ontology-based description framework which takes the ontology approach to the next step, where existing description frameworks are in- corporated into the ontology-based framework, allowing discovery mechanisms to cover multiple existing domains. In this manner, existing protocols and networking approaches can participate in semantically-rich discovery processes. This framework also includes a system architecture developed for the purpose of reconciling existing home network solutions with the ontology-based discovery process. This work also describes an implementation of the approach and is deployed within a home-network environment. This implementation involves existing home networking frameworks, protocols and components, allowing the claims of this work to be examined and evaluated from a ‘real-world’ perspective