The use of preferences in query answering, both in traditional databases and in ontology-based data access, has recently received much attention, due to its many real-world applications. In this paper, we tackle the problem of top-k query answering in Datalog+/– ontologies subject to the querying user’s preferences and a collection of (subjective) reports of other users. Here, each report consi...

An Efficient Interaction Framework for Mobile Web Services Abdullah Abdullatif Almuaibid Supervising Professor: Xumin Liu, Ph.D. Having the latest technological devices is becoming more of a necessity these days rather than a luxury as it was only a decade ago. Among these advancements, the smart phone has grown in popularity significantly. This is due to a variety of reasons but it would have ...

The use of cache memory makes the processing of access in a faster rate. The main purpose of cache memory is to give faster memory access by which the data read should be fast and at the same period d provide less expensive and types of semiconductor memories which are of large memory size. There is correspondingly main memory which is large but slow together with a smaller as well faster cache...

Pervasive computing applications have unique characteristics that preclude the use of traditional access control models, such as Role-Based Access Control (RBAC), for their protection. Such models do not take into account contextual information before making access decisions and cannot handle the dynamism inherent in pervasive computing applications. Towards this end, we propose new spatio-temp...

Scientific simulations often generate massive amounts of data used for debugging, restarts, and scientific analysis and discovery. Challenges that practitioners face using these types of big data are unique. Of primary importance is speed of writing data during a simulation, but this need for fast I/O is at odds with other priorities, such as data access time for visualization and analysis, eff...

Data grid is a composition of different services for accessing and manipulating data in a distributed environment. One of the major problems is high access time of remote queries in the data grid. In this paper we present a scheme for data cache management system for data intensive applications on Data Grid, which provides a faster access to remote data by intelligently managing the copies in t...

This paper proposes an exponential replicate broadcasting (ERB) algorithm for data dissemination to improve data access efficiency. The proposed ERB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical model to derive t...

Replica placement is one of the important factors to improve performance in data grid systems. A good replica placement algorithm can result in good performance gains. It should be mentioned that, these algorithms or strategies are dependent on architecture of the data grid. By considering different kinds of architecture in data grid systems, a true representation of a grid is a general graph. ...

Data grid is a distributed collection of storage and computational resources that are not boundedwithin a geophysical location. It is a fast growing area of research and providing efficient data access andmaximum data availability is a challenging task. To achieve this task, data is replicated to different sites. A number of data replication techniques have been presented for data grids. All re...