Search results for "database."

Accelerating data queries on Hadoop framework by using compact data formats

2016

There are massive amounts of data generated from IoT, online transactions, click streams, emails, logs, posts, social networking interactions, sensors, mobile phones and their applications etc. The question is where and how to store these data in order to provide faster data access. Understanding and handling Big Data is a big challenge. The research direction in Big Data projects using Hadoop Technology, MapReduce kind of framework and compact data formats such as RCFile, SequenceFile, ORC, Avro, Parquet shows that only two data formats (Avro and Parquet) support schema evolution and compression in order to utilize less storage space. In this paper, file formats like Avro and Parquet are c…

Infiniviz: Taking Quake 3 Arena on a Large-Scale Display System to the Next Level

2018

The authors of this paper have previously presented a large-scale display system called Infiniviz in other publications. Infiniviz attempts to improve network bandwidth consumption and computational performance compared to other existing large-scale display systems. Since the previous publications have been made in early development stages of Infiniviz, only the overview of the software architecture and details of hardware implementation have been presented so far. This paper contains a real-life test of Infiniviz running Quake 3 Arena at a resolution of 9600 x 5400 at 24 fps. Also, in this paper, the authors have tried to match their results to what has been published by other researchers …

HybridS: A Scheme for Secure Distributed Data Storage in WSNs

2008

In unattended wireless sensor networks (WSNs), data is stored locally or at designated nodes upon sensing, and users can access it on demand. This paradigm can improve energy efficiency by making use of the upcoming cheap and large flash memory, as well as system robustness. Nevertheless, the security and dependability of distributed storage are critical for the applicability of such WSNs. In this paper, we propose a secure and dependable data storage scheme by taking advantages of secret sharing and Reed-Solomon code, which has computational security and yet maintains optimal data size. The extensive analysis verifies our scheme can provide secure and dependable data storage in WSNs in the…

Schema theory: A new approach?

1987

Building Semantic Trees from XML Documents

2016

International audience; The distributed nature of the Web, as a decentralized system exchanging information between heterogeneous sources, has underlined the need to manage interoperability, i.e., the ability to automatically interpret information in Web documents exchanged between different sources, necessary for efficient information management and search applications. In this context, XML was introduced as a data representation standard that simplifies the tasks of interoperation and integration among heterogeneous data sources, allowing to represent data in (semi-) structured documents consisting of hierarchically nested elements and atomic attributes. However, while XML was shown most …

A novel XML document structure comparison framework based-on sub-tree commonalities and label semantics

2012

International audience; XML similarity evaluation has become a central issue in the database and information communities, its applications ranging over document clustering, version control, data integration and ranked retrieval. Various algorithms for comparing hierarchically structured data, XML documents in particular, have been proposed in the literature. Most of them make use of techniques for finding the edit distance between tree structures, XML documents being commonly modeled as Ordered Labeled Trees. Yet, a thorough investigation of current approaches led us to identify several similarity aspects, i.e., sub-tree related structural and semantic similarities, which are not sufficient…

Building Ontologies from XML Data Sources

2009

In this paper, we present a tool called X2OWL that aims at building an OWL ontology from an XML datasource. This method is based on XML schema to automatically generate the ontology structure, as well as, a set of mapping bridges. The presented method also includes a refinement step that allows to clean the mapping bridges and possibly to restructure the generated ontology.

Requirements for XML document database systems

2001

The shift from SGML to XML has created new demands for managing structured documents. Many XML documents will be transient representations for the purpose of data exchange between different types of applications, but there will also be a need for effective means to manage persistent XML data as a database. In this paper we explore requirements for an XML database management system. The purpose of the paper is not to suggest a single type of system covering all necessary features. Instead the purpose is to initiate discussion of the requirements arising from document collections, to offer a context in which to evaluate current and future solutions, and to encourage the development of proper …

An overview on XML similarity: Background, current trends and future directions

2009

In recent years, XML has been established as a major means for information management, and has been broadly utilized for complex data representation (e.g. multimedia objects). Owing to an unparalleled increasing use of the XML standard, developing efficient techniques for comparing XML-based documents becomes essential in the database and information retrieval communities. In this paper, we provide an overview of XML similarity/comparison by presenting existing research related to XML similarity. We also detail the possible applications of XML comparison processes in various fields, ranging over data warehousing, data integration, classification/clustering and XML querying, and discuss some…

Extensible User-Based XML Grammar Matching

2009

International audience; XML grammar matching has found considerable interest recently due to the growing number of heterogeneous XML documents on the web and the increasing need to integrate, and consequently search and retrieve XML data originated from different data sources. In this paper, we provide an approach for automatic XML grammar matching and comparison aiming to minimize the amount of user effort required to perform the match task. We propose an open framework based on the concept of tree edit distance, integrating different matching criterions so as to capture XML grammar element semantic and syntactic similarities, cardinality and alternativeness constraints, as well as data-ty…