Search results for "informations"
showing 10 items of 428 documents
Errors and Complications in SQL Query Formulation
2018
SQL is taught in almost all university level database courses, yet SQL has received relatively little attention in educational research. In this study, we present a database management system independent categorization of SQL query errors that students make in an introductory database course. We base the categorization on previous literature, present a class of logical errors that has not been studied in detail, and review and complement these findings by analyzing over 33,000 SQL queries submitted by students. Our analysis verifies error findings presented in previous literature and reveals new types of errors, namely logical errors recurring in similar manners among different students. We…
Schema-Based Visual Queries over Linked Data Endpoints
2019
We present the option to use the schema-based visual query tool ViziQuer over realistic Linked Data endpoints. We describe the tool meta-schema structure and the means for the endpoint schema retrieval both from an OWL ontology and from a SPARQL endpoint. We report on a store of the endpoint-specific schemas and the options to support the schema presentation to the end-user both as a class tree within the environment and as external visual diagram.
Semantic Portal for Legislative Information
2006
Semantic portals enabled by Semantic Web technologies have been suggested to provide a point of access to an integrated body of information about some domain. In the area of e-Government there are multiple possible domains for semantic portals, one of them being legislative work. In this paper we propose a semantic portal based on a rich metadata repository to support the retrieval of legislative information. The portal provides process oriented semantic browsing capabilities. A prototype of the portal has been implemented for the retrieval of Finnish legislative information.
Publish By Example
2008
We propose an approach for producing database publishing programs by example. The main idea is to interactively build an example document, representative of the program output. The system infers from this document, without ambiguity, the publishing program. The end-user does not need to know a programming language, a query language or the database schema.
A Novel Approach to Improve the Accuracy of Web Retrieval
2010
General purpose search engines utilize a very simple view on text documents: They consider them as bags of words. It results that after indexing, the semantics of documents is lost. In this paper, we introduce a novel approach to improve the accuracy of Web retrieval. We utilize the WordNet and WordNet SenseRelate All Words Software as main tools to preserve the semantics of the sentences of documents and user queries. Nouns and verbs in the WordNet are organized in the tree hierarchies. The word meanings are presented by numbers that reference to the nodes on the semantic tree. The meaning of each word in the sentence is calculated when the sentence is analyzed. The goal is to put each nou…
From Databases to Ontologies
2009
This chapter introduces the UML profile for OWL as an essential instrument for bridging the gap between the legacy relational databases and OWL ontologies. We address one of the long-standing relational database design problems where initial conceptual model (a semantically clear domain conceptualization ontology) gets “lost” during conversion into the normalized database schema. The problem is that such “loss” makes database inaccessible for direct query by domain experts familiar with the conceptual model only. This problem can be avoided by exporting the database into RDF according to the original conceptual model (OWL ontology) and formulating semantically clear queries in SPARQL over t…
ViziQuer: A Tool to Explore and Query SPARQL Endpoints
2011
The presented tool uses a novel approach to explore and query a SPARQL endpoint. The tool is simple to use as a user needs only to enter an address of a SPARQL endpoint of one's interest. The tool will extract and visualize graphically the data schema of the endpoint. The user will be able to overview the data schema and use it to construct a SPARQL query according to the data schema. The tool can be downloaded from http://viziquer.lumii.lv. There is also additional information and help on how to use it in practice.
Using UDDI for Publishing Metadata of the Semantic Web
2006
Although UDDI does not provide support for semantic search, retrieval and storage, it is already accepted as an industrial standard and a huge number of services already store their service specifications in UDDI. Objective of this paper is to analyze possibilities and ways to use UDDI registry to allow utilization of meta-data encoded according to Semantic Web standards for semantic-based description, discovery and integration of web resources in the context of needs of two research projects: “Adaptive Services Grid” and “SmartResource”. We present an approach of mapping RDFS upper concepts to UDDI data model using tModel structure, which makes possible to store semantically annotated reso…
Part-of-speech labeling for Reuters database
2015
Even if the Vector Space Model used for document representation in information retrieval systems integrates a small quantity of knowledge it continues to be used due to its computational cost, speed execution and simplicity. We try to improve this document representation by adding some syntactic information such as the parts of speech. In this paper, we have evaluated three different tagging algorithms in order to select the most suitable tagger for using it to tag the Reuters dataset. In this work, we have evaluated the taggers using only five different parts of speech: noun, verb, adverb, adjective and others. We considered these particular tags being the most representative for describin…
Additional file 3: of Living alone and positive mental health: a systematic review
2019
Search strategies by database. This file presents the search strategies by each database employed in the study. (DOCX 35 kb)