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Across a wide range of domains, there is an urgent need for a wellfounded approach to incorporating uncertain and incomplete knowledge into formal domain ontologies. Although this subject is receiving increasing attention from ontology researchers, there is as yet no broad consensus on the definition of a probabilistic ontology and on the most suitable approach to extending current ontology languages to support uncertainty. This paper presents two contributions to developing a coherent framework for probabilistic ontologies: (1) a formal definition of a probabilistic ontology, and (2) an extension of the OWL Web Ontology Language that is consistent with our formal definition. This extension, PR-OWL, is based on Multi-Entity Bayesian Networks (MEBN), a first-order Bayesian logic that unifies Bayesian probability with First-Order Logic. As such, PR-OWL combines the full representation power of OWL with the flexibility and inferential power of Bayesian logic.
2006
Across a wide range of domains, there is an urgent need for a wellfounded approach to incorporating uncertain and incomplete knowledge into formal domain ontologies. Although this subject is receiving increasing attention from ontology researchers, there is as yet no broad consensus on the definition of a probabilistic ontology and on the most suitable approach to extending current ontology languages to support uncertainty. This paper presents two contributions to developing a coherent framework for probabilistic ontologies: (1) a formal definition of a probabilistic ontology, and (2) an extension of the OWL Web Ontology Language that is consistent with our formal definition. This extension, PROWL , is based on Multi-Entity Bayesian Networks (MEBN), a first-order Bayesian logic that unifies Bayesian probability with First-Order Logic. As such, PROWL combines the full representation power of OWL with the flexibility and inferential power of Bayesian logic.
This paper addresses a major weakness of current technologies for the Semantic Web, namely the lack of a principled means to represent and reason about uncertainty. This not only hinders the realization of the original vision for the Semantic Web, but also creates a barrier to the development of new, powerful features for general knowledge applications that require proper treatment of uncertain phenomena. We propose to extend OWL, the ontology language recommended by the World Wide Web Consortium (W3C), to provide the ability to express probabilistic knowledge. The new language, PR-OWL, will allow legacy ontologies to interoperate with newly developed probabilistic ontologies. PR-OWL will move beyond the current limitations of deterministic classical logic to a full first-order probabilistic logic. By providing a principled means of modeling uncertainty in ontologies, PR-OWL will serve as a supporting tool for many applications that can benefit from probabilistic inference within an ontology language, thus representing an important step toward the W3C's vision for the Semantic Web.
International Journal of Approximate Reasoning, 2017
Recent years have witnessed an increasingly mature body of research on the Semantic Web (SW), with new standards being developed and more complex problems being addressed. As complexity increases in SW applications, so does the need to cope with uncertainty. Several approaches to uncertainty representation and reasoning in the SW have emerged. Among these is Probabilistic Web Ontology Language (PR-OWL), which provides a means of representing uncertainty in ontologies expressed in Web Ontology Language (OWL). PROWL allows values of random variables to range over OWL datatypes, following an approach suggested by Poole et al. to formalizing the association between random variables from probabilistic theories with the individuals, classes and properties from ontological languages such as OWL.
2005
This paper addresses a major weakness of current technologies for the Semantic Web, namely the lack of a principled means to represent and reason about uncertainty. This not only hinders the realization of the original vision for the Semantic Web, but also creates a barrier to the development of new, powerful features for general knowledge applications that require proper treatment of uncertain phenomena. We propose to extend OWL, the ontology language recommended by the World Wide Web Consortium (W3C), to provide the ability to express probabilistic knowledge. The new language, PROWL , will allow legacy ontologies to interoperate with newly developed probabilistic ontologies. PROWL will move beyond the current limitations of deterministic classical logic to a full first-order probabilistic logic. By providing a principled means of modeling uncertainty in ontologies, PROWL will serve as a supporting tool for many applications that can benefit from probabilistic inference within an ontology language, thus representing an important step toward the W3C's vision for the Semantic Web.
One of the major weaknesses of current research on the Semantic Web (SW) is the lack of proper means to represent and reason with uncertainty. A number of recent efforts from the SW community, the W3C, and others have recently emerged to address this gap. Such efforts have the positive side effect of bringing together two fields of research that have been apart for historical reasons, the artificial intelligence and the SW communities. One example of the potential research gains of this convergence is the current development of Probabilistic OWL (PR-OWL), an extension of the OWL Web Ontology Language that provides a framework to build probabilistic ontologies, thus enabling proper representation and reasoning with uncertainty within the SW context. PR-OWL is based on Multi-Entity Bayesian Networks (MEBN), a first-order probabilistic logic that combines the representational power of first-order logic (FOL) and Bayesian Networks (BN). However, PR-OWL and MEBN are still in development, lacking a software tool that implements their underlying concepts. The development of UnBBayes-MEBN, an open source, Java-based application that is currently in alpha phase (public release March 08), addresses this gap by providing both a GUI for building probabilistic ontologies and a reasoner based on the PR-OWL/MEBN framework. This work focuses on the major challenges of UnBBayes-MEBN implementation, describes the features already implemented, and provides an overview of the major algorithms, mainly the one used for building a Situation Specific Bayesian Network (SSBN) from a MEBN Theory.
In order to meet the demands envisioned for the battlefield of the 21 st century, the DoD is pressing for rapid adoption of the Global Information Grid (GIG), a centerpiece of its transformation towards network-centric operations. Among the enabling technologies being leveraged by GIG-related efforts is the widespread adoption of Service Oriented Architecture (SOA), a powerful approach for effectively connecting consumers and providers of information and data processing resources. However, implementing SOA in the GIG context is a major challenge that requires semantic interoperability among service descriptions. To achieve semantic interoperability, it is necessary to establish mappings between vocabularies of independently developed resources from both providers and consumers. Many research efforts have relied on ontologies as a possible solution to this problem, but with limited success to date. We argue that in such an environment, a principled means for representing uncertainty is needed; something not found in common ontologies. This paper proposes the combined use of probabilistic ontologies and SOA for a Net-Centric framework, and presents a conceptual scheme for battlefield information exchange systems with different levels of service descriptions (including legacy and probabilistic enabled descriptions).
2015
Probabilistic OWL (PR-OWL) improves the Web Ontology Language (OWL) with the ability to treat uncertainty using Multi-Entity Bayesian Networks (MEBN). PROWL 2 presents a better integration with OWL and its underlying logic, allowing the creation of ontologies with probabilistic and deterministic parts. However, there are scalability problems since PROWL 2 is built upon OWL 2 DL which is a version of OWL based on description logic SROIQ(D) and with high complexity. To address this issue, this paper proposes PROWL 2 RL, a scalable version of PROWL based on OWL 2 RL profile and triplestores (databases based on RDF triples). OWL 2 RL allows reasoning in polynomial time for the main reasoning tasks. This paper also presents First-Order expressions accepted by this new language and analyzes its expressive power. A comparison with the previous language presents which kinds of problems are more suitable for each version of PROWL .
2011 IEEE International Conference on Systems, Man, and Cybernetics, 2011
Uncertainty handling for semantic networks is a difficult problem which has slowed the effort to fully develop a semantic web.
Iswc, 2006
Service Oriented Architecture (SOA) is a key technology to support interoperability among data and processing resources. Semantic interoperability requires mapping between vocabularies of independently developed resources, a task fraught with uncertainty. Probabilistic ontologies enable representation of knowledge in domains characterized by uncertainty. As such, they promise to improve the quality of service descriptions, enable more thorough analysis of service composition opportunities, and provide a theoretically sound methodology for semantic mapping under uncertainty. This paper defines probabilistic ontologies, discusses their application to SOA, and presents a conceptual scheme for using a federation of ontologies (with both common and probabilistic ontologies) as a semantic mapping tool for service oriented information exchange systems with different levels of service descriptions (including legacy and probabilistic enabled descriptions). 1 Semantic Interoperability in the Semantic Web and Service Oriented Architecture Frameworks A fundamental tenet of the Semantic Web (SW) vision is that adding semantics to web resources can spark a paradigm shift from information-based data exchange to knowledge-based data-exchange. HTML syntax hard-codes a limited single-purpose set of semantic categories. In contrast, the Semantic Web envisions resources annotated with well-defined, explicitly represented semantics that provides the basis for rich description and reasoning. Explicit semantics is essential for appropriate processing of syntactically identical but semantically different terms (e.g., "Washington" the President, the city, or the football team). Ontologies, or shared repositories of precisely defined concepts expressed in standardized languages, are a vital tool for enabling semantic interoperability among web resources. Thus, ontologies are a means for transforming the current "Web of shared data" into a "Web of shared knowledge."
2016
The Uncertainty Modeling Process for Semantic Technologies (UMP-ST) is an incremental and iterative approach that covers the difficulty in maintaining and evolving existing POs [5]. It is a general methodology for the majority of the existing semantic technologies which support uncertainty. One of them is the Probabilistic OWL (PR-OWL), which is a language for representing Multi-Entity Bayesian Networks (MEBN). The modeling of a PO using UMP-ST methodology and MEBN/PR-OWL representation is supported by UnBBayes, a framework for building probabilistic graphical models and performing plausible reasoning. Although there is a guidance described by UMP-ST to model a PO, the implementation of a PO is painful and repetitive. Nowadays, the user needs to build the ontology from the zero in a specific technology, even if the user models the PO in UMP-ST. A proper integration that helps the user to implement the PO such as an intermediate structure makes implementation easier than build the PO...
IGI Global eBooks, 2018
During the past years, ontologies are widely used for representing knowledge of complex domains. Despite that the ontologies (classical ontologies) have become standard for representing knowledge; however, they are not able to represent and reason with uncertainty which is one of the characteristics of the world that must be handled. Probabilistic Ontologies have come to remedy this defect. This paper is part of this framework in which the authors have proposed a new method of probabilistic ontology construction, named Prob-Ont, by integrating uncertainty to elements of OWL ontology (especially to instances and/or relations). As a case study, the authors have constructed a probabilistic ontology for the domain of scientific documentation system (dblp).
The use of ontologies is on the rise, as they facilitate interoperability and provide support for automation. Today, ontologies are popular for research in areas such as the Semantic Web, knowledge engineering, artificial intelligence and knowledge management. However, many real world problems in these disciplines are burdened by incomplete information and other sources of uncertainty which traditional ontologies cannot represent. Therefore, a means to incorporate uncertainty is a necessity. Probabilistic ontologies extend current ontology formalisms to provide support for representing and reasoning with uncertainty. Representation of uncertainty in real-world problems requires probabilistic ontologies, which integrate the inferential reasoning power of probabilistic representations with the first-order expressivity of ontologies. This paper introduces a systematic approach to probabilistic ontology development through a reference architecture which captures the evolution of a traditional ontology into a probabilistic ontology implementation for real-world problems. The Reference Architecture for Probabilistic Ontology Development catalogues and defines the processes and artifacts necessary for the development, implementation and evaluation of explicit, logical and defensible probabilistic ontologies developed for knowledgesharing and reuse in a given domain.
2014
: The use of ontologies is on the rise, as they facilitate interoperability and provide support for automation. Today, ontologies are popular in areas such as the Semantic Web, knowledge engineering, Artificial Intelligence and knowledge management. However, many real world problems in these disciplines are burdened by incomplete information and other sources of uncertainty which traditional ontologies cannot represent. Therefore, a means to incorporate uncertainty is a necessity. Probabilistic ontologies extend current ontology formalisms to provide support for representing and reasoning with uncertainty. Traditional ontologies provide a hierarchical structure of entity classes and a formal way of expressing their relationships with first-order expressivity, which supports logical reasoning. However, they lack built-in, principled support to adequately account for uncertainty. Applying simple probability annotations to ontologies fails to convey the structure of the probabilistic r...
Probabilistic ontologies incorporate uncertain and incomplete information into domain ontologies, allowing uncertainty in attributes of and relationships among domain entities to be represented in a consistent and coherent manner. The probabilistic ontology language PR-OWL provides OWL constructs for representing multi-entity Bayesian network (MEBN) theories. Although compatibility with OWL was a major design goal of PR-OWL, the initial version fell short in several important respects. These shortcomings are addressed by the latest version, PR-OWL 2. This paper provides an overview of the new features of PR-OWL 2 and presents a case study of a probabilistic ontology in the maritime domain. The case study describes the process of constructing a PR-OWL 2 ontology using an existing OWL ontology as a starting point.
We present BUNDLE, a reasoner able to perform reasoning on probabilistic knowledge bases according to the semantics DISPONTE. In DISPONTE the axioms of a probabilistic ontology can be annotated with an epistemic or a statistical probability. The epistemic probability represents a degree of confidence in the axiom, while the statistical probability considers the populations to which the axiom is applied. BUNDLE exploits an underlying OWL DL reasoner, which is Pellet, that is able to return explanations for a query. However, it can work well with any reasoner able to return explanations for a query. The explanations are encoded in a Binary Decision Diagram from which the probability of the query is computed.
Although several languages have been proposed for dealing with uncertainty in the Semantic Web (SW), almost no support has been given to ontological engineers on how to create such probabilistic ontologies (PO). This task of modeling POs has proven to be extremely difficult and hard to replicate. This paper presents the first tool in the world to implement a process which guides users in modeling POs, the Uncertainty Modeling Process for Semantic Technologies (UMP-ST). The tool solves three main problems: the complexity in creating POs; the difficulty in maintaining and evolving existing POs; and the lack of a centralized tool for documenting POs. Besides presenting the tool, which is implemented as a plug-in for UnBBayes, this papers also presents how the UMP-ST plug-in could have been used to build the Probabilistic Ontology for Procurement Fraud Detection and Prevention in Brazil, a proof-of-concept use case created as part of a research project at the Brazilian Office of the General Comptroller (CGU).
2012
We present DISPONTE, a semantics for probabilistic ontologies that is based on the distribution semantics for probabilistic logic programs. In DISPONTE the axioms of a probabilistic ontology can be annotated with an epistemic or a statistical probability. The epistemic probability represents a degree of confidence in the axiom, while the statistical probability considers the populations to which the axiom is applied.
2006
Ontologies have become ubiquitous in currentgeneration information systems. An ontology is an explicit, formal representation of the entities and relationships that can exist in a domain of application. Following a well-trodden path, initial research in computational ontology has neglected uncertainty, developing almost exclusively within the framework of classical logic. As appreciation grows of the limitations of ontology formalisms that cannot represent uncertainty, the demand from user communities increases for ontology formalisms with the power to express uncertainty. Support for uncertainty is essential for interoperability, knowledge sharing, and knowledge reuse. Bayesian ontologies are used to describe knowledge about a domain with its associated uncertainty in a principled, structured, sharable, and machine-understandable way. This paper considers Multi-Entity Bayesian Networks (MEBN) as a logical basis for Bayesian ontologies, and describes PROWL , a MEBN-based probabilistic extension to the ontology language OWL. To illustrate the potentialities of Bayesian probabilistic ontologies in the development of AI systems, we present a case study in information security, in which ontology development played a key role.
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