Mehrdad Jahangiri

Learn More
The Discrete Wavelet Transform is a proven tool for a wide range of database applications. However, despite broad acceptance, some of its properties have not been fully explored and thus not exploited, particularly for two common forms of multidimensional decomposition. We introduce two novel operations for wavelet transformed data, termed SHIFT and SPLIT,(More)
Data analysis systems require range-aggregate query answering of large multidimensional datasets. We provide the necessary framework to build a retrieval system capable of providing fast answers with progressively increasing accuracy in support of range-aggregate queries. In addition, with error forecasting, we provide estimations on the accuracy of the(More)
Variable bit rate (VBR) compression for media streams allocates more bits to complex scenes and fewer bits to simple scenes. This results in a higher and more uniform visual and aural quality. The disadvantage of the VBR technique is that it results in bursty network traffic and uneven resource utilization when streaming media. In this study we propose an(More)
Online Scientific Applications (OSA) require statistical analysis of large multidimensional datasets. Towards this end, we have designed and developed a data storage and retrieval system, called ProDA, which deploys wavelet transform and provides fast approximate answers with progressively increasing accuracy in support of the OSA queries. ProDA employs a(More)
ProDA employs wavelets to support exact, approximate, and progressive OLAP queries on large multidimensional datasets, while keeping update costs relatively low. ProDA not only supports online execution of ad hoc analytical queries on massive datasets, but also extends the set of supported analytical queries to include the entire family of polynomial(More)
INTRODUCTION Following the constant technological advancements that provide more processing power and storage capacity, scientific applications have emerged as a new field of interest for the database community. Such applications, termed Online Science Applications (OSA), require continuous interaction with datasets of multidimen-sional nature, mainly for(More)
  • 1