Distributed Description Logics Research Articles

Modeling Location Preferences in Service Composition Using Distributed Knowledgebase

Successful Composition of a web service in dynamic environment is a big challenge and important research issue. Several service designers may produce similar or different services. In automatic service selection environment service may fail due to functional dissimilarity and non-functional property of the services (QoS) attributes. In this context, any service can be preferred for particular location. These preferences act as QoS attribute and play important role to minimize failure of the service. Knowledge of these location preferences also helps in dynamic service selection. In composition, services are present in heterogeneous environment with different location preferences. In this paper, we have developed a knowledge base for the location preferences, which we have termed as Location Affinity. We have also incorporated semantic matching phenomenon along with affinity matching of the service for distributed environment using distributed description logic.

Handling Non-determinism with Description Logics using a Fork/Join Approach

The increasing use of Ontologies, formulated using expressive Description Logics, for time sensitive applications necessitates the development of fast (near realtime) reasoning tools. Mul- ticore processors are nowadays widespread across desktop, laptop, server, and even smartphone and tablets devices. The rise of such powerful execution environments calls for new parallel and distributed Description Logics (DLs) reasoning algorithms. Many sophisticated optimizations have been explored and have considerably enhanced DL reasoning with light ontologies. Non- determinism remains a main source of complexity for implemented systems handling ontologies relying on more expressive logics. In this work, we explore handling non-determinism with DL languages enabling qualified cardinality restrictions. We implement a fork/join parallel framework into our tableau-based al- gebraic reasoner, which handles qualified cardinality restrictions and nominals using in-equation solving. The preliminary results are encouraging and show that using a parallel framework with algebraic reasoning is worth investigating and more promising than parallelizing standard tableau-based reasoning.Â

A Revised Distributed Interpretation for Ontology Integration

Under the background of information integration, the semantics of ontology integration is still an open issue. In this paper, we propose a revised distributed interpretation which is adapted from distributed description logics. In our proposal, ontology integration is taken as global ontology and local ontologies connected by ontology mapping. They are respectively interpreted with DL semantics and Semantic Import semantics. In this way, our method can facilitate understanding and maintenance of ontology integration.

AUGMENTING SUBSUMPTION PROPAGATION IN DISTRIBUTED DESCRIPTION LOGICS

Distributed description logics (DDL) enable reasoning with multiple ontologies interconnected by directional semantic mapping, called bridge rules. Bridge rules map concepts of a source ontology into concepts of a target ontology. Concept subsumptions of the source ontology can be propagated according to a propagation pattern expressed by means of bridge rules into concept subsumptions of the target ontology. In the basic formulation of DDL, such a propagation is mostly limited to cases when pairs of ontologies are directly linked by means of bridge rules. However, when more than two ontologies are involved, one would expect that subsumption propagates along chains of ontologies linked by bridge rules, but the semantics of DDL is too weak to support this behavior. In a recent study, an adjusted semantics for DDL that supports subsumption propagation through chains of bridge rules has been introduced. This study makes use of a so-called compositional consistency requirement that has been employed before in package-based description logics. While the results concerning subsumption propagation under the adjusted semantics are encouraging, there are important drawbacks. In this article we take a wider perspective, and propose a study of several different alternative extensions of the DDL semantics. For each of them we study the formal properties, and we select the one that, according to our analysis, constitutes a good compromise, and for this case we provide a sound and complete tableaux decision procedure.

Debugging Mappings between Biomedical Ontologies: Preliminary Results from the NCBO BioPortal Mapping Repository

The ability to provide semantic mappings between multiple large biomedical ontologies is considered as a very important, albeit labor-intensive and errorprone task. To facilitate such a process, several approaches for collaborative ontology mapping building and sharing have been proposed in the recent past. However, despite the improvements in community-wide mappings development, more often the mapping rules are redundant, incoherent, and at times, incorrect. In this paper, we present an approach for identifying such “erroneous mappings” using Distributed Description Logics. Specifically, we illustrate how logical reasoning can be used to discover semantic inconsistencies caused by erroneous mappings, and provide preliminary results of experiments based on the National Center for Biomedical Ontology BioPortal mapping repository.

Debugging Mappings between Biomedical Ontologies: Preliminary Results from the NCBO BioPortal Mapping Repository

The ability to provide semantic mappings between multiple large biomedical ontologies is considered as a very important, albeit labor-intensive and errorprone task. To facilitate such a process, several approaches for collaborative ontology mapping building and sharing have been proposed in the recent past. However, despite the improvements in community-wide mappings development, more often the mapping rules are redundant, incoherent, and at times, incorrect. In this paper, we present an approach for identifying such “erroneous mappings” using Distributed Description Logics. Specifically, we illustrate how logical reasoning can be used to discover semantic inconsistencies caused by erroneous mappings, and provide preliminary results of experiments based on the National Center for Biomedical Ontology BioPortal mapping repository.

Reasoning and change management in modular ontologies

The benefits of modular representations are well known from many areas of computer science. While in software engineering modularization is mainly a vehicle for supporting distributed development and re-use, in knowledge representation, the main goal of modularization is efficiency of reasoning. In this paper, we concentrate on the benefits of modularization in the context of ontologies, explicit representations of the terminology used in a domain. We define a formal representation for modular ontologies based on the notion of Distributed Description Logics and introduce an architecture that supports local reasoning by compiling implied axioms. We further address the problem of guaranteeing the correctness and completeness of compiled knowledge in the presence of changes in different modules. We propose a heuristic for analyzing changes and their impact on compiled knowledge and guiding the process of updating compiled information that can often reduce the effort of maintaining a modular ontology by avoiding unnecessary re-compilation.

Software Agent Technology

Software agent technology is an exciting paradigm which can be efficiently applied to many distributed computing problems, particularly those that require dynamic behavior to reach a solution. Software agent technology has emerged as an enhancement of, if not an alternative to, the traditional client/server model in such an environment. Mobile agents can migrate to a desired remote peer and take advantage of local processing rather then relying on remote procedure calls (RPC) across the network, as in the case of client/server systems. Also, agents are entities which function continuously and autonomously in a particular environment, and are able to carry out activities in a flexible and intelligent manner that is responsive to the dynamically changing environment. Ideally, an agent that functions continuously would be able to learn from experience and have capabilities to adapt to ad-hoc events and apply suitable functionality depending on the circumstances. Employment of the agent technology in the traditional client-server environments could result in more robust, flexible and better performing solutions for many applications. In this special issue, we have collected five cutting edge research papers which are the extended versions of a selected group of the papers already published in Intelligent Agent Systems 2005 (IAS 05) special track at the 18th International FLAIRS Conference. The first paper, Agents Go Traveling, by D. O'Kane, D. Marsh, S. Shen, R. Tynan and G. M. P. O'Hare, is concerned with the infrastructure support for nomadic agents. The authors have introduced the Agent Travel Metaphor (ATM) which offers a metaphor fostering integration of control and security. The second paper is entitled Exploiting Shared Ontologies with Default Information for Web Agents, by Y. Ma, B. Jin and M. Zhou. This paper uses distributed description logic (DDL) to model the mappings between ontologies used by different agents and further makes an extension to the DDL model. A WS-Agreement Based Resource Negotiation Framework for Mobile Agents is the title of the third paper by D. G. A. Mobach, B. J. Overeinder, and F. M. T Brazier. This paper presents a negotiation infrastructure with which agents acquire time-limited resource contracts through negotiation with one or more mediators instead of individual hosting systems. The fourth paper, Agent Composition via Role-Based Infrastructures, by G. Cabri, proposes to build infrastructures based on roles, which are abstractions that enable the composition of different agents in an open scenario. Finally the last paper, unlike the first four papers, presents an application of software agents for support of student mobility. This paper is authored by M. Ganzha, W. Kuranowski and M. Paprzycki. We have tried our best to present quality works in this special issue and certainly hope that we have achieved this goal. Shahram Rahimi, Raheel Ahmad