The numbers of files in file systems have increased dramatically in recent years. Office workers spend much time and effort searching for the documents required for their jobs. To reduce these costs, we propose a new method for recommending files and operations on them. Existing technologies for recommendation, such as collaborative filtering, suffer from two problems. First, they can only work...

The data access object (DAO) pattern tries to decouple the access to data from its underlying storage. Persisting data currently relies heavily on the type of database used: Relational database, object-oriented databases, flat files. It would be preferable to chose the type of database used during the deployment phase instead of the design phase. By using data access objects the data is decoupl...

2D convolution and 2D transforms, such as wavelet transform and discrete cosine transform (DCT), are widely used in image and video processing. To reduce the computation complexity, these algorithms are often implemented in two separable passes of 1D processing (e.g., row-wise processing followed by column-wise processing). For example, the number of multiplications of a direct N x N 2D DCT is ...

Phenomenal improvements in the computational performance of multiprocessors have not been matched by comparable gains in I/O system performance. This imbalance has resulted in I/O becoming a significant bottleneck for many scientific applications. One key to overcoming this bottleneck is improving the performance of parallel file systems. The design of a high-performance parallel file system re...

The Internet enables global sharing of data across organizational boundaries. Traditional access control mechanisms are intended for one or a small number of machines under common administrative control, and rely on maintaining a centralized database of user identities. They fail to scale to a large user base distributed across multiple organizations. This survey provides a taxonomy of decentra...

In a wide superscalar processor, the amount of time it takes to execute an application depends on the instruction latency and the amount of instruction level parallelism (ILP) that can be extracted from the application. One important factor which influences the instruction latency is the number of cycles it takes to access the register file. Whether it is a CISC architecture or a RISC architect...

Acknowledgements I would like to thank Professor Dennis Shasha for his continued support and guidance. I am also grateful to my two co-researchers Chris Harrison and Stacey Kuznetsov.

Multimedia applications are sensitive to I/O latency and jitter when accessing data in secondary storage. Transparent adaptive prefetching (TAP) uses software feedback to provide multimedia applications with file system quality of service (QoS) guarantees. We are investigating how QoS requirements can be communicated and how they can be met by adaptive resource management. A preliminary test of...

A JPEG Quality Transcoder (JQT) converts a JPEG image file that was encoded with low image quality to a larger JPEG image file with reduced visual artifacts, without access to the original uncompressed image. In this article, we describe technology for JQT design that takes a pattern recognition approach to the problem, using a database of images to train statistical models of the artifacts int...

Despite increasingly distributed internet information sources with diverse storage formats and access-control constraints, most of the end applications (e.g., filters and media players) that view and manipulate data from these sources operate against a traditional file-based interface. These legacy applications need to be rewritten to access remote sources, or need to rely upon ad hoc intermedi...