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Mohamed F. Mokbel |
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SpatialHadoop is an open source MapReduce framework with built-in support for spatial data. It employs the MapReduce programming paradigm for distributed processing to build a general purpose tool for large scale analysis of spatial data on large clusters. Users can interact easily with SpatialHadoop through a high level language with built-in support for spatial data types and spatial operations. Existing spatial data sets can be loaded in SpatialHadoop with the built in spatial data types point, polygon and rectangle. SpatialHadoop is also extensible and more data types can be added by users. In addition, the data sets are stored efficiently using built-in indexes (Grid file or R-tree) which speed up the retrieval and processing of these data sets. Users can build an index of their choice with a single command that runs in parallel on the machines in the cluster. Once the index is built, users can start analyzing their data sets using the built in spatial operations (range query, k nearest neighbor and spatial join). The extensibility of SpatialHadoop allows users to implement more spatial operations as MapReduce programs.
For more information, please visit: "http://spatialhadoop.cs.umn.edu/"
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Monitoring personal locations with a potentially untrusted server poses privacy threats to the monitored individuals. To this end, we propose a privacy-preserving location monitoring system for wireless sensor networks. In our system, we design two in-network location anonymization algorithms, namely, resource- and quality-aware algorithms, that aim to enable the system to provide high quality location monitoring services for system users, while preserving personal location privacy. Both algorithms rely on the well established k-anonymity privacy concept to enable trusted sensor nodes to provide the aggregate location information of monitored persons for our system. Each aggregate location is in a form of a monitored area A along with the number of monitored persons residing in A, where A contains at least k persons. The resource-aware algorithm aims to minimize communication and computational cost, while the quality-aware algorithm aims to maximize the accuracy of the aggregate locations by minimizing their monitored areas. To utilize the aggregate location information to provide location monitoring services, we use a spatial histogram approach that estimates the distribution of the monitored persons based on the gathered aggregate location information. The estimated distribution is used to provide location monitoring services through answering range queries. | ||
This project tackles a major privacy concern in current location-based services where users have to continuously report their locations to the database server in order to obtain the service. For example, a user asking about the nearest gas station has to report her exact location. With untrusted servers, reporting the location information may lead to several privacy threats. In this paper, we present Casper1; a new framework in which mobile and stationary users can entertain location-based services without revealing their location information. Casper consists of two main components, the location anonymizer and the privacy-aware query processor. The location anonymizer blurs the users’ exact location information into cloaked spatial regions based on user-specified privacy requirements. The privacy-aware query processor is embedded inside the location-based database server in order to deal with the cloaked spatial areas rather than the exact location information. | ||
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