scholarly journals An Effective Approach for Accurate Estimation of Trust of Distant Information Sources in the Semantic Web

Author(s):  
V.G. Bintzios ◽  
T.G. Papaioannou ◽  
G.D. Stamoulis
2013 ◽  
Vol 60 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Alexandru Napoleon Sireteanu

Abstract In the beginning World Wide Web was syntactic and the content itself was only readable by humans. The modern web combines existing web technologies with knowledge representation formalisms. In this sense, the Semantic Web proposes the mark-up of content on the web using formal ontology that structure essential data for the purpose of comprehensive machine understanding. On the syntactical level, standardization is an important topic. Many standards which can be used to integrate different information sources have evolved. Beside the classical database interfaces like ODBC, web-oriented standard languages like HTML, XML, RDF and OWL increase in importance. As the World Wide Web offers the greatest potential for sharing information, we will base our paper on these evolving standards.


2011 ◽  
Vol 26 (4) ◽  
pp. 445-486 ◽  
Author(s):  
Juan F. Sequeda ◽  
Syed Hamid Tirmizi ◽  
Oscar Corcho ◽  
Daniel P. Miranker

AbstractThe Semantic Web anticipates integrated access to a large number of information sources on the Internet represented as Resource Description Framework (RDF). Given the large number of websites that are backed by SQL databases, methods that automate the translation of those databases to RDF are crucial. One approach, taken by a number of researchers, is to directly map the SQL schema to an equivalent Web Ontology Language (OWL) or RDF Schema representation, which in turn, implies an RDF representation for the relational data. This paper reviews this research, and derives a consolidated, overarching set of translation rules expressible as a stratified Datalog program. We present all the possible key combinations in an SQL schema and consider their implied semantic properties. We review the approaches and characterize them with respect to the scope of their coverage of SQL constructs.


2010 ◽  
Vol 103 (3) ◽  
pp. 1518-1531 ◽  
Author(s):  
Jordan B. Brayanov ◽  
Maurice A. Smith

Which is heavier: a pound of lead or a pound of feathers? This classic trick question belies a simple but surprising truth: when lifted, the pound of lead feels heavier—a phenomenon known as the size–weight illusion. To estimate the weight of an object, our CNS combines two imperfect sources of information: a prior expectation, based on the object's appearance, and direct sensory information from lifting it. Bayes' theorem (or Bayes' law) defines the statistically optimal way to combine multiple information sources for maximally accurate estimation. Here we asked whether the mechanisms for combining these information sources produce statistically optimal weight estimates for both perceptions and actions. We first studied the ability of subjects to hold one hand steady when the other removed an object from it, under conditions in which sensory information about the object's weight sometimes conflicted with prior expectations based on its size. Since the ability to steady the supporting hand depends on the generation of a motor command that accounts for lift timing and object weight, hand motion can be used to gauge biases in weight estimation by the motor system. We found that these motor system weight estimates reflected the integration of prior expectations with real-time proprioceptive information in a Bayesian, statistically optimal fashion that discounted unexpected sensory information. This produces a motor size–weight illusion that consistently biases weight estimates toward prior expectations. In contrast, when subjects compared the weights of two objects, their perceptions defied Bayes' law, exaggerating the value of unexpected sensory information. This produces a perceptual size–weight illusion that biases weight perceptions away from prior expectations. We term this effect “anti-Bayesian” because the bias is opposite that seen in Bayesian integration. Our findings suggest that two fundamentally different strategies for the integration of prior expectations with sensory information coexist in the nervous system for weight estimation.


Author(s):  
W. R. Schucany ◽  
G. H. Kelsoe ◽  
V. F. Allison

Accurate estimation of the size of spheroid organelles from thin sectioned material is often necessary, as uniquely homogenous populations of organelles such as vessicles, granules, or nuclei often are critically important in the morphological identification of similar cell types. However, the difficulty in obtaining accurate diameter measurements of thin sectioned organelles is well known. This difficulty is due to the extreme tenuity of the sectioned material as compared to the size of the intact organelle. In populations where low variance is suspected the traditional method of diameter estimation has been to measure literally hundreds of profiles and to describe the “largest” as representative of the “approximate maximal diameter”.


2007 ◽  
Vol 12 (3) ◽  
pp. 196-205 ◽  
Author(s):  
Géry d'Ydewalle ◽  
Wim De Bruycker

Abstract. Eye movements of children (Grade 5-6) and adults were monitored while they were watching a foreign language movie with either standard (foreign language soundtrack and native language subtitling) or reversed (foreign language subtitles and native language soundtrack) subtitling. With standard subtitling, reading behavior in the subtitle was observed, but there was a difference between one- and two-line subtitles. As two lines of text contain verbal information that cannot easily be inferred from the pictures on the screen, more regular reading occurred; a single text line is often redundant to the information in the picture, and accordingly less reading of one-line text was apparent. Reversed subtitling showed even more irregular reading patterns (e.g., more subtitles skipped, fewer fixations, longer latencies). No substantial age differences emerged, except that children took longer to shift attention to the subtitle at its onset, and showed longer fixations and shorter saccades in the text. On the whole, the results demonstrated the flexibility of the attentional system and its tuning to the several information sources available (image, soundtrack, and subtitles).


Author(s):  
Virginie Crollen ◽  
Julie Castronovo ◽  
Xavier Seron

Over the last 30 years, numerical estimation has been largely studied. Recently, Castronovo and Seron (2007) proposed the bi-directional mapping hypothesis in order to account for the finding that dependent on the type of estimation task (perception vs. production of numerosities), reverse patterns of performance are found (i.e., under- and over-estimation, respectively). Here, we further investigated this hypothesis by submitting adult participants to three types of numerical estimation task: (1) a perception task, in which participants had to estimate the numerosity of a non-symbolic collection; (2) a production task, in which participants had to approximately produce the numerosity of a symbolic numerical input; and (3) a reproduction task, in which participants had to reproduce the numerosity of a non-symbolic numerical input. Our results gave further support to the finding that different patterns of performance are found according to the type of estimation task: (1) under-estimation in the perception task; (2) over-estimation in the production task; and (3) accurate estimation in the reproduction task. Moreover, correlation analyses revealed that the more a participant under-estimated in the perception task, the more he/she over-estimated in the production task. We discussed these empirical data by showing how they can be accounted by the bi-directional mapping hypothesis ( Castronovo & Seron, 2007 ).


2005 ◽  
pp. 60-71
Author(s):  
E. Serova ◽  
O. Shick

Russian policy makers argue that agriculture suffers from decapitalization due to financial constraints faced by producers. This view is the basis for the national agricultural policy, which emphasizes reimbursement of input costs and substitutes government and quasi-government organizations for missing market institutions. The article evaluates the availability of purchased farm inputs, the efficiency of their use, the main problems in the emergence of market institutions, and the impact of government policies. The analysis focuses on five groups of purchased inputs: farm machinery, fertilizers, fuel, seeds, and animal feed. The information sources include official statistics and data from two original surveys.


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