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Lantzaki, C., Yannakis, T., Tzitzikas, Y., Analyti, A. Generating Synthetic RDF Data with Connected Blank Nodes for Benchmarking. Video Journal of Semantic Data Management Abstracts Issue 1, Volume 3 (2014)
Elbedweihy, K., Mazumdar, S., Wrigley, S., Ciravegna, F. NL-Graphs: A Hybrid Approach toward Interactively Querying Semantic Data. . Video Journal of Semantic Data Management Abstracts Issue 1, Volume 3 (2014)
More information about the event could be found here
Recently, representation of context dependent knowledge in the Semantic Web has been recognized as a relevant issue and a number of logic based solutions have been proposed in this regard: among them, in our previous works we presented the Contextualized Knowledge Repository (CKR) framework. A CKR knowledge base has a two layered structure, modelled by a global context and a set of local contexts: the global context not only contains the metaknowledge defining the properties of local contexts, but also holds the global (context independent) object knowledge that is shared by all of the local contexts. In many practical cases, however, it is desirable to leave the possibility to “override” the global object knowledge at the local level, by recognizing the axioms that can allow exceptional instances in the local contexts. This clearly requires to add a
notion of non monotonicity across the global and the local parts of a CKR. In this paper we present an extension to the semantics of CKR to introduce such notion of defeasible axioms. By extending a previously proposed datalog translation, we obtain a representation for CKR as a datalog program with negation under answer set semantics. This representation can be exploited as the basis for implementation of query answering for the proposed extension of CKR.
Representation of context dependent knowledge in the Semantic Web has been recognized as a relevant issue: as a consequence, a number of logic based formalisms have been proposed in this regard. In response to this need, in previous works, we presented the description logic-based Contextualized Knowledge Repository (CKR) framework. Starting from this point, the first contribution of the paper is an extension of CKR with the possibility to represent defaults in context dependent axioms and a translation of extended CKRs to datalog programs with negation under answer sets semantics. The translation generates datalog programs which are sound and complete w.r.t. instance checking in CKRs. Exploiting this result, we have developed as a second contribution a prototype implementation that compiles a CKR based on OWL2RL to a datalog program. Finally, we compare our approach with major non-monotonic formalisms for description logics and contextual knowledge representation.AttachmentSize DL2014-BozEitSer14.pdf287.35 KB
Given the increasing amount of sensitive RDF data available on theWeb, it becomes critical to guarantee secure access to this content. The problem becomes even more challenging in the presence of RDFS inference, where inferred knowledge needs to be protected in the same way as explicit one. State of the art models for RDF access control annotate triples with concrete values that denote whether a triple can be accessed or not. In such approaches, the computation of the corresponding values
for the inferred triples is hard-coded; this creates several problems in the presence of updates in the data, or, most importantly, when the access control policies change. We answer the above challenges by proposing an abstract model where the access labels are abstract tokens, and the computation of inferred labels is modelled through abstract operators. We demonstrate our model through the HACEA (Health Access Control Enforcement Application) that provides simple access control/privacy functionalities in the context of a medical use case.
VLDB is a premier annual international forum for data management and database researchers, vendors, practitioners, application developers, and users. The conference will feature research talks, tutorials, demonstrations, and workshops. It will cover current issues in data management, database and information systems research. Data management and databases remain among the main technological cornerstones of emerging applications of the twenty-first century.
VLDB2014 will take place atHangzhou, which is one of the best tourism cities in China. Hangzhou is also one of the eight ancient capitals in Chinese history and one in the first group of National Famous Historical and Cultural Cities. The West Lake in Hangzhou, known as the "earthly paradise", is one of the top attractions in China and abroad. Besides, Hangzhou is the hometown of tea and silk. Longjing Green Tea is the No. 1 among the top ten Chinese teas. attracts many tourists every year, and offers numerous opportunities for sightseeing (e.g., West Lake, Lingyin Temple, Qiantang River), outdoor activities (e.g., hiking, cycling, boating), cluture tasting (e.g., tea, silk, traditional cuisine, Grand Canal ), as well as fun (e.g., Songcheng Theme Park, "Impression of West Lake" light opera).
More at http://www.vldb.org/2014/
co-located with VLDB 2014
Following the 1st International workshop on Benchmarking RDF Systems (BeRSys 2013) the aim of the BeRSys 2014 workshop is to provide a discussion forum where researchers and industrials can meet to discuss topics related to the performance of RDF systems. BeRSys 2014 is the only workshop dedicated to benchmarking different aspects of RDF engines - in the line of TPCTC series of workshops.The focus of the workshop is to expose and initiate discussions on best practices, different application needs and scenarios related to different aspects of RDF data management.
Communicating straight with customers, in an efficient and effective manner is still a desideratum for small, medium and large companies alike. With the rapid development of ICT technologies, including Internet, Web-based communication, and recently Social Media, the number of possibilities to interact directly with customers has grown event larger. For small and medium companies in general and those in the touristic industry in particular, direct communication with customers has been always seen as an enabler for massive direct sales. However, these expectations are still to be fulfilled. In this talk we analyze the causes of this failure and propose a solution on how effective and efficient communication for touristic industry should be realized. We perform an empirical analysis of the usage pattern of Internet technology in the touristic domain. We introduce first the challenges faced nowadays by touristic service providers in terms of online and mobile booking, commission payments and social media. We then have a look at key technologies and communication channels that touristic service providers must use in order to be highly visible online including static, dynamic, sharing, collaboration, social media, fora, vocabularies, semantic formats, etc. We analyze the uptake of these technologies and channels by hotels, hotels chains, destinations and booking channels and point out on one hand how well intermediaries i.e. booking channels (e.g. booking.com, hrs.de, etc.) are using them, while on the other hand, touristic service providers are failing. Finally, we show how these technologies and communication channels should be used for effective direct marketing in the touristic industry by means of a real pilot developed in collaboration with the touristic association of service providers located in the city of Innsbruck and its surroundings i.e. Tourismusverband Innsbruck (TVb).
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