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Parallelizing Federated SPARQL Queries in Presence of Replicated Data [chapter]

Thomas Minier, Gabriela Montoya, Hala Skaf-Molli, Pascal Molli
2017 Lecture Notes in Computer Science  
Replicating data fragments in Linked Data improves data availability and performances of federated query engines.  ...  In this paper, we extend replication-aware federated query engines with a replication-aware parallel join operator: PeNeLoop.  ...  This work is partially supported through the FaBuLA project, part of the AtlanSTIC 2020 program.  ... 
doi:10.1007/978-3-319-70407-4_33 fatcat:pntzjq5fdjfvdjsk3fpdff7op4

FedX: Optimization Techniques for Federated Query Processing on Linked Data [chapter]

Andreas Schwarte, Peter Haase, Katja Hose, Ralf Schenkel, Michael Schmidt
2011 Lecture Notes in Computer Science  
With FedX we achieve a significant improvement in query performance over state-of-the-art federated query engines.  ...  Motivated by the ongoing success of Linked Data and the growing amount of semantic data sources available on the Web, new challenges to query processing are emerging.  ...  These numbers immediately explain the improvements in query performance of FedX. With our optimization techniques, FedX is able to minimize the number of subqueries necessary to process the queries.  ... 
doi:10.1007/978-3-642-25073-6_38 fatcat:3mgfop65s5dmbpmkterq4j2hve

FedSearch: Efficiently Combining Structured Queries and Full-Text Search in a SPARQL Federation [chapter]

Andriy Nikolov, Andreas Schwarte, Christian Hütter
2013 Lecture Notes in Computer Science  
We extend the SPARQL algebra to incorporate keyword search clauses as first-class citizens and apply novel optimization techniques to improve the query processing efficiency while maintaining a meaningful  ...  However, executing hybrid search queries in a federation of multiple data sources presents a number of challenges due to data source heterogeneity and lack of statistical data about keyword selectivity  ...  FedSearch further improves on this due to parallelization.  ... 
doi:10.1007/978-3-642-41335-3_27 fatcat:tt7gztkmsjg5zbypo2rbgf45ta

Ladda: SPARQL Queries in the Fog of Browsers [chapter]

Arnaud Grall, Pauline Folz, Gabriela Montoya, Hala Skaf-Molli, Pascal Molli, Miel Vander Sande, Ruben Verborgh
2017 Lecture Notes in Computer Science  
Acknowledgement We thank Thibaud Courtoison, Maël Quémard and Sylvain Vuylsteke, students of the Computer Science Department at the University of Nantes for implementing the interface of Ladda.  ...  Ladda enables inter-query parallelism on the client-side, significantly reduces the time to obtain all results (makespan) and improves the overall throughput.  ...  This realizes a fog of browsers [3] in which decentralized end-user devices cooperate to process SPARQL queries.  ... 
doi:10.1007/978-3-319-70407-4_24 fatcat:mldox5aobre3rewffzgg5rn5gu

QEF-LD - A Query Engine for Distributed Query Processing on Linked Data

Regis Pires Magalhães, José Maria Monteiro, Vânia Maria P. Vidal, José Antônio Fernandes de Macêdo, Macedo Sousa Maia, Fábio Porto, Marco A. Casanova
2013 Proceedings of the 15th International Conference on Enterprise Information Systems  
However, achieving an efficient execution of such a SPARQL federated query is hard.  ...  Linked data applications express integrated views using the SPARQL query language. A SPARQL federated query is submitted to a query engine that processes it over the distributed SPARQL endpoints.  ...  iii) using data cache, indexes and statistics to improve query performance; (iv) creating a framework to automate all steps of federated query processing, where QED-LD will be used as the query execution  ... 
doi:10.5220/0004443401850192 dblp:conf/iceis/MagalhaesMVMMPC13 fatcat:cnecadttmfgfrdxm6iu4q7imxu

Federated query processing on linked data: a qualitative survey and open challenges

Damla Oguz, Belgin Ergenc, Shaoyi Yin, Oguz Dikenelli, Abdelkader Hameurlain
2015 Knowledge engineering review (Print)  
Finally, we discuss the major challenges of federated query processing on linked data.  ...  In this paper, we initially give an overview of query processing approaches used in this interlinked and distributed environment, and then focus on federated query processing on linked data.  ...  Acknowledgement This work is partially supported by The Scientific and Technological Research Council of Turkey (TUBITAK).  ... 
doi:10.1017/s0269888915000107 fatcat:aksyotsj7zedvkxl6lmc54d7wy

A Vertical PRF Architecture for Microblog Search

Flávio Martins, João Magalhães, Jamie Callan
2018 Proceedings of the 2018 ACM SIGIR International Conference on Theory of Information Retrieval - ICTIR '18  
The hypothesis is that using an expansion corpus organized into verticals for expanding the query, will lead to a more efficient query expansion process and improved retrieval effectiveness.  ...  improving ranking.  ...  A federated query expansion architecture also affords faster response times via parallel work.  ... 
doi:10.1145/3234944.3234960 dblp:conf/ictir/MartinsMC18 fatcat:bl23jknwpneghna4yy7xxqjbeq

FedX: A Federation Layer for Distributed Query Processing on Linked Open Data [chapter]

Andreas Schwarte, Peter Haase, Katja Hose, Ralf Schenkel, Michael Schmidt
2011 Lecture Notes in Computer Science  
We present FedX, a project which extends the Sesame Framework with a federation layer that enables efficient query processing on distributed Linked Open Data sources.  ...  Hand in hand with this structure new challenges to query processing are arising.  ...  during query processing. • Filter pushing: SPARQL filter expressions are pushed down whenever possible to allow for early evaluation. • Parallel processing: Concurrency is exploited by means of multithreaded  ... 
doi:10.1007/978-3-642-21064-8_39 fatcat:5tn35zysovc3jarbwk5ds7grmm

Scalable Queries Over Log Database Collections [chapter]

Minpeng Zhu, Khalid Mahmood, Tore Risch
2015 Lecture Notes in Computer Science  
FLOQ provides general and extensible mechanisms for efficient processing of queries over different kinds of distributed data sources.  ...  The collection of log databases is dynamically changing when new sites are dynamically added or removed from the federation.  ...  This query processing over log database federations answers research question four.  ... 
doi:10.1007/978-3-319-20424-6_17 fatcat:uu5rpgzxo5g2xidzlhrbcvgzbi

Exploring Cloud Opportunities from an Array Database Perspective

Alex Dumitru, Vlad Merticariu, Peter Baumann
2014 Proceedings of Workshop on Data analytics in the Cloud - DanaC'14  
We present an enhancement of the well-established Array DBMS rasdaman with intra-query distribution capabilities: requests, incoming in the form of database queries, are broken into sub-queries which are  ...  The splitting strategies ensure that the network's processing power is fully exploited, while at the same time enabling optimizations such as network traffic minimization.  ...  ACKNOWLEDGMENTS Part of this work has been supported through EU FP7 EarthServer ( Thanks to George Merticariu for the cloud benchmarking suite.  ... 
doi:10.1145/2627770.2627775 dblp:conf/sigmod/DumitruMB14 fatcat:ehl6bpww4bahfblp64ynt424oq

cSELENE: Privacy Preserving Query Retrieval System on Heterogeneous Cloud Data [article]

Diyah Puspitaningrum
2018 arXiv   pre-print
In this paper we discuss preserving-privacy system and threat model, the format of federated data, the parallel programming (GPU programming and shared/memory systems), the parallel and secure algorithm  ...  It is not only about the data privacy concern but also about how can those federated data can be querying from cloud directly in fast and securely way.  ...  For fast processing each computation on fragments of all databases in DB is processed parallel using MapReduce.  ... 
arXiv:1805.01275v1 fatcat:j5b3567ys5c3vmbzzk5udtr2vu

On efficiently processing nearest neighbor queries in a loosely coupled set of data sources

Thomas Schwarz, Markus Iofcea, Matthias Grossmann, Nicola H�nle, Daniela Nicklas, Bernhard Mitschang
2004 Proceedings of the 12th annual ACM international workshop on Geographic information systems - GIS '04  
We propose a family of algorithms for processing nearest neighbor (NN) queries in an integration middleware that provides federated access to numerous loosely coupled, autonomous data sources connected  ...  Additionally, we propose to use only moderate parallelism instead of querying all relevant data sources at the same time.  ...  Distributed and Parallel Nearest Neighbor Queries Previous work on distributed and parallel processing of similarity queries has focussed on how to decluster the data [2, 7, 8, 9, 15, 22] : they partition  ... 
doi:10.1145/1032222.1032250 dblp:conf/gis/SchwarzIGHNM04 fatcat:zxvxu2gzzbethkns3kszwkdpv4

Federation in Cloud Data Management: Challenges and Opportunities

Gang Chen, H. V. Jagadish, Dawei Jiang, David Maier, Beng Chin Ooi, Kian-Lee Tan, Wang-Chiew Tan
2014 IEEE Transactions on Knowledge and Data Engineering  
, the variety of data types stored, and the variety of query interfaces presented by those systems.  ...  Companies are increasingly moving their data processing to the cloud, for reasons of cost, scalability, and convenience, among others.  ...  With an increasing number of compute nodes as the data processing systems scale out to improve parallelism, the likelihood of node failure also increases.  ... 
doi:10.1109/tkde.2014.2326659 fatcat:34qjmo33oze3liroahklxtqusq

Learning from the History of Distributed Query Processing - A Heretic View on Linked Data Management

Heiko Betz, Francis Gropengießer, Katja Hose, Kai-Uwe Sattler
2012 International Semantic Web Conference  
Recently, much effort has been put into the development of techniques for query processing over Linked Data.  ...  Being based upon techniques originally developed for distributed and federated databases, some of them inherit the same or similar problems.  ...  Only simple, highly selective queries profit from the parallel execution within a federated system.  ... 
dblp:conf/semweb/BetzGHS12 fatcat:uqnvywxmtzgehmkja3suvdqgfa

WawPart: Workload-Aware Partitioning of Knowledge Graphs [article]

Amitabh Priyadarshi, Krzysztof J. Kochut
2022 arXiv   pre-print
Our evaluation results demonstrate the performance improvement in workload processing time.  ...  The resulting partitioning aims to reduces the number of distributed joins and improve the workload performance.  ...  ParMETIS [12] and LogGP [13] are state-of-the-art parallel graph processing systems.  ... 
arXiv:2203.14888v1 fatcat:22ciguafmvetjk5jo245munpii
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