An infrastructure for semantic web portals

This paper presents our Semantic Web portal infrastructure, which focuses on how to enhance knowledge access in traditional Web portals by gathering and exploiting semantic metadata. Special attention is paid to three important issues that affect the performance of knowledge access: i) high quality metadata acquisition, which concerns how to ensure high quality while gathering semantic metadata from heterogeneous data sources; ii) semantic search, which addresses how to meet the information querying needs of ordinary end users who are not necessarily familiar with the problem domain or the supported query language; and iii) semantic browsing, which concerns how to help users understand and explore the problem domain.

PowerAqua:fishing the semantic web

The Semantic Web (SW) offers an opportunity to develop novel, sophisticated forms of question answering (QA). Specifically, the availability of distributed semantic markup on a large scale opens the way to QA systems which can make use of such semantic information to provide precise, formally derived answers to questions. At the same time the distributed, heterogeneous, large-scale nature of the semantic information introduces significant challenges. In this paper we describe the design of a QA system, PowerAqua, designed to exploit semantic markup on the web to provide answers to questions posed in natural language. PowerAqua does not assume that the user has any prior information about the semantic resources. The system takes as input a natural language query, translates it into a set of logical queries, which are then answered by consulting and aggregating information derived from multiple heterogeneous semantic sources.

SemSearch:a search engine for the semantic web

Existing semantic search tools have been primarily designed to enhance the performance of traditional search technologies but with little support for ordinary end users who are not necessarily familiar with domain specific semantic data, ontologies, or SQL-like query languages. This paper presents SemSearch, a search engine, which pays special attention to this issue by providing several means to hide the complexity of semantic search from end users and thus make it easy to use and effective.

AquaLog : an ontology-driven question answering system to interface the semantic web

The semantic web (SW) vision is one in which rich, ontology-based semantic markup will become widely available. The availability of semantic markup on the web opens the way to novel, sophisticated forms of question answering. AquaLog is a portable question-answering system which takes queries expressed in natural language (NL) and an ontology as input, and returns answers drawn from one or more knowledge bases (KB). AquaLog presents an elegant solution in which different strategies are combined together in a novel way. AquaLog novel ontology-based relation similarity service makes sense of user queries.

ClaiMaker : weaving a semantic web of research papers

The usability of research papers on the Web would be enhanced by a system that explicitly modelled the rhetorical relations between claims in related papers. We describe ClaiMaker, a system for modelling readers’ interpretations of the core content of papers. ClaiMaker provides tools to build a Semantic Web representation of the claims in research papers using an ontology of relations. We demonstrate how the system can be used to make inter-document queries.

Sierra : cooperative request-response for resource management in disasters using semantic web principles

Disasters cause widespread harm and disrupt the normal functioning of society, and effective management requires the participation and cooperation of many actors. While advances in information and networking technology have made transmission of data easier than it ever has been before, communication and coordination of activities between actors remain exceptionally difficult. This paper employs semantic web technology and Linked Data principles to create a network of intercommunicating and inter-dependent on-line sites for managing resources. Each site publishes available resources openly and a lightweight opendata protocol is used to request and respond to requests for resources between sites in the network.

Internet search:subdivision-based interactive query expansion and the soft semantic web

The expansion of the Internet has made the task of searching a crucial one. Internet users, however, have to make a great effort in order to formulate a search query that returns the required results. Many methods have been devised to assist in this task by helping the users modify their query to give better results. In this paper we propose an interactive method for query expansion. It is based on the observation that documents are often found to contain terms with high information content, which can summarise their subject matter. We present experimental results, which demonstrate that our approach significantly shortens the time required in order to accomplish a certain task by performing web searches.

Transparent Scheduling of Composite Web Services

Composite Web Services (CWS) aggregate multiple Web Services in one logical unit to accomplish a complex task (e.g. business process). This aggregation is achieved by defining a workflow that orchestrates the underlying Web Services in a manner consistent with the desired functionality. Since CWS can aggregate atomic and other CWS they foster the development of service layers and reuse of already existing functionality. An important issue in the deployment of services is their run-time performance under various loads. Due to the complex interactions of the underlying services, a CWS they can exhibit problematic and often difficult to predict behaviours in overload situations. This paper focuses on the use of request scheduling for improving CWS performance in overload situations. Different scheduling policies are investigated in regards to their effectiveness in helping with bulk arrivals.

Extending Object-Oriented Network Protocols via alternative Transportation Bindings (Web Services over XMPP)

Distributed and/or composite web applications are driven by intercommunication via web services, which employ application-level protocols, such as SOAP. However, these protocols usually rely on the classic HTTP for transportation. HTTP is quite efficient for what it does — delivering web page content, but has never been intended to carry complex web service oriented communication. Today there exist modern protocols that are much better fit for the job. Such a candidate is XMPP. It is an XML-based, asynchronous, open protocol that has built-in security and authentication mechanisms and utilizes a network of federated servers. Sophisticated asynchronous multi-party communication patterns can be established, effectively aiding web service developers. This paper’s purpose is to prove by facts, comparisons, and practical examples that XMPP is not only better suited than HTTP to serve as middleware for web service protocols, but can also contribute to the overall development state of web services.

Digitization and Preservation of City Landmarks Using Limited and Free Web Services

This paper presents a practical approach for digitizing city landmarks based on free and limited Web resources. The digital replicas are then placed on the Web using popular services, like Google earth, and are accessible to a huge user base. The method is easily applicable and quite valuable to organizations with limited funding.

Museum Collections and the Semantic Web

The paper discusses some current trends in the area of development and use of semantic portals for accessing heterogeneous museum collections on the Semantic Web. The presentation is focused on some issues concerning metadata standards for museums, museum collections ontologies and semantic search engines. A number of design considerations and recommendations are formulated.

Reconciling OWL and non-monotonic rules for the semantic web

We propose a description logic extending SROIQ (the description logic underlying OWL 2 DL) and at the same time encompassing some of the most prominent monotonic and nonmonotonic rule languages, in particular Datalog extended with the answer set semantics. Our proposal could be considered a substantial contribution towards fulfilling the quest for a unifying logic for the Semantic Web. As a case in point, two non-monotonic extensions of description logics considered to be of distinct expressiveness until now are covered in our proposal. In contrast to earlier such proposals, our language has the "look and feel" of a description logic and avoids hybrid or first-order syntaxes. © 2012 The Author(s).

Certificação de composições de serviços web semânticos

This thesis presents a certification method for semantic web services compositions which aims to statically ensure its functional correctness. Certification method encompasses two dimensions of verification, termed base and functional dimensions. Base dimension concerns with the verification of application correctness of the semantic web service in the composition, i.e., to ensure that each service invocation given in the composition comply with its respective service definition. The certification of this dimension exploits the semantic compatibility between the invocation arguments and formal parameters of the semantic web service. Functional dimension aims to ensure that the composition satisfies a given specification expressed in the form of preconditions and postconditions. This dimension is formalized by a Hoare logic based calculus. Partial correctness specifications involving compositions of semantic web services can be derived from the deductive system proposed. Our work is also characterized by exploiting the use of a fragment of description logic, i.e., ALC, to express the partial correctness specifications. In order to operationalize the proposed certification method, we developed a supporting environment for defining the semantic web services compositions as well as to conduct the certification process. The certification method were experimentally evaluated by applying it in three different proof concepts. These proof concepts enabled to broadly evaluate the method certification

GraniteNights - A Multi-Agent Visit Scheduler Utilising Semantic Web Technology

Postprint

An Empirical Investigation of Learning From the Semantic Web

Peer reviewed