4,865 research outputs found

    A semantic language for querying anonymous web sources

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    A great deal of work has been carried out in recent years to facilitate access to data and information available on the Web. Proposals converge in two additional areas which consist in providing the sources with semantic annotations and in designing languages and tools that are capable of using these annotations. However, a large number of sources have not yet been annotated suitably. Besides, languages and existing tools do not allow the user to formulate "blind" queries without knowing the sources. To overcome these two limitations, in this paper we propose a flexible query language which allows a user to query sources in an anonymous way without knowing their existence and their structure. Queries can be solved by a system which in advance discovers potential sources and memorizes their schemas. We clarify how such a system can function

    Conjunctive query inseparability of OWL 2 QL TBoxes

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    The OWL2 profile OWL 2 QL, based on the DL-Lite family of description logics, is emerging as a major language for developing new ontologies and approximating the existing ones. Its main application is ontology based data access, where ontologies are used to provide background knowledge for answering queries over data. We investigate the corresponding notion of query inseparability (or equivalence) for OWL 2 QL ontologies and show that deciding query inseparability is PSpace-hard and in ExpTime. We give polynomial-time (incomplete) algorithms and demonstrate by experiments that they can be used for practical module extraction

    VOODB: A Generic Discrete-Event Random Simulation Model to Evaluate the Performances of OODBs

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    International audiencePerformance of object-oriented database systems (OODBs) is still an issue to both designers and users nowadays. The aim of this paper is to propose a generic discrete-event random simulation model, called VOODB, in order to evaluate the performances of OODBs in general, and the performances of optimization methods like clustering in particular. Such optimization methods undoubtedly improve the performances of OODBs. Yet, they also always induce some kind of overhead for the system. Therefore, it is important to evaluate their exact impact on the overall performances. VOODB has been designed as a generic discrete-event random simulation model by putting to use a modelling approach, and has been validated by simulating the behavior of the O2 OODB and the Texas persistent object store. Since our final objective is to compare object clustering algorithms, some experiments have also been conducted on the DSTC clustering technique, which is implemented in Texas. To validate VOODB, performance results obtained by simulation for a given experiment have been compared to the results obtained by benchmarking the real systems in the same conditions. Benchmarking and simulation performance evaluations have been observed to be consistent, so it appears that simulation can be a reliable approach to evaluate the performances of OODBs

    A NoSQL-Based Framework for Managing Home Services

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    Individuals and companies have an increasing need for services by specialized suppliers in their homes or premises. These services can be quite different and can require different amounts of resources. Service suppliers have to specify the activities to be performed, plan those activities, allocate resources, follow up after their completion and must be able to react to any unexpected situation. Various proposals were formulated to model and implement these functions; however, there is no unified approach that can improve the efficiency of software solutions to enable economy of scale. In this paper, we propose a framework that a service supplier can use to manage geo-localized activities. The proposed framework is based on a NoSQL data model and implemented using the MongoDB system. We also discuss the advantages and drawbacks of a NoSQL approach

    Can [125I]-Iodocyanopindolol Label β3-Adrenoceptors in Rat Urinary Bladder?

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    β3-Adrenoceptors have been demonstrated to mediate urinary bladder smooth muscle relaxation but proof of their expression at the protein level has been missing because of lack of suitable antibodies or radioligands. As among various available radioligands [125I]-iodocyanopindolol ([125I]-ICYP) exhibited the smallest problems in labeling cloned human β3-adrenoceptors in previous studies, we have explored its suitability to label β3-adrenoceptors in rat urinary bladder in saturation and competition radioligand binding experiments. Rat lung was used as an internal control and exhibited all characteristics expected from this tissue with regard to β1/β2-adrenoceptor labeling. Saturation and competition binding studies with [125I]-ICYP in rat bladder yielded saturable binding sites with an affinity compatible with β3-adrenoceptors. In competition experiments various agonists and antagonists largely exhibited a profile compatible with a population consisting largely of β3-adrenoceptors. However, the binding competition properties of ICI 118,551 and SR 59,230A were not easily explained by the idea of labeling a homogeneous β3-adrenoceptor population but interpretation of the data was limited by a high degree of non-specific binding in [125I]-ICYP concentrations required to label the receptors. We conclude that [125I]-ICYP can be used to label tissue β3-adrenoceptors but results obtained with this ligand have to be interpreted with caution
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