166,688 research outputs found
A Distributed Query Processing Engine
Wireless sensor networks (WSNs) are formed of tiny, highly energy-constrained sensor nodes that are equipped with wireless transceivers. They may be mobile and are usually deployed in large numbers in unfamiliar environments. The nodes communicate with one another by autonomously creating ad-hoc networks which are subsequently used to gather sensor data. WSNs also process the data within the network itself and only forward the result to the requesting node. This is referred to as in-network data aggregation and results in the substantial reduction of the amount of data that needs to be transmitted by any single node in the network. In this paper we present a framework for a distributed query processing engine (DQPE) which would allow sensor nodes to examine incoming queries and autonomously perform query optimisation using information available locally. Such qualities make a WSN the perfect tool to carryout environmental\ud
monitoring in future planetary exploration missions in a reliable and cost effective manner
Partout: A Distributed Engine for Efficient RDF Processing
The increasing interest in Semantic Web technologies has led not only to a
rapid growth of semantic data on the Web but also to an increasing number of
backend applications with already more than a trillion triples in some cases.
Confronted with such huge amounts of data and the future growth, existing
state-of-the-art systems for storing RDF and processing SPARQL queries are no
longer sufficient. In this paper, we introduce Partout, a distributed engine
for efficient RDF processing in a cluster of machines. We propose an effective
approach for fragmenting RDF data sets based on a query log, allocating the
fragments to nodes in a cluster, and finding the optimal configuration. Partout
can efficiently handle updates and its query optimizer produces efficient query
execution plans for ad-hoc SPARQL queries. Our experiments show the superiority
of our approach to state-of-the-art approaches for partitioning and distributed
SPARQL query processing
Distributed Inference and Query Processing for RFID Tracking and Monitoring
In this paper, we present the design of a scalable, distributed stream
processing system for RFID tracking and monitoring. Since RFID data lacks
containment and location information that is key to query processing, we
propose to combine location and containment inference with stream query
processing in a single architecture, with inference as an enabling mechanism
for high-level query processing. We further consider challenges in
instantiating such a system in large distributed settings and design techniques
for distributed inference and query processing. Our experimental results, using
both real-world data and large synthetic traces, demonstrate the accuracy,
efficiency, and scalability of our proposed techniques.Comment: VLDB201
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