Date of Award

Summer 2003

Document Type


Degree Name

Doctor of Philosophy (PhD)


Computer Science

Committee Director

Kurt Maly

Committee Director

Stewart N. T. Shen

Committee Member

Hussien Abdel-Wahab

Committee Member

Frank Thames

Committee Member

Mohammad Zubair


The objective of this research is to study the issues involved in building a digital library that contains data streams and allows event-based retrieval. “Digital Libraries are storehouses of information available through the Internet that provide ways to collect, store, and organize data and make it accessible for search, retrieval, and processing” [29]. Data streams are sources of information for applications such as news-on-demand, weather services, and scientific research, to name a few. A data stream is a sequence of data units produced over a period of time. Examples of data streams are video streams, audio stream, and sensor readings. Saving data streams in digital libraries is advantageous because of the services provided by digital libraries such as archiving, preservation, administration, and access control. Events are noteworthy occurrences that happen during data streams. Events are easier to remember than specific time instances at which they occur; hence using them for retrieval is more commensurate with human behavior and can be more efficient via direct accessing instead of scanning. The focus of this research is not only on storing data streams in a digital library and using event-based retrieval, but also on relating streams and playing them back at the same time, possibly in a synchronized manner, to facilitate better understanding in research or other working situations.

Our approach for this research starts by considering digital libraries for: stock market, news streams, census bureau statistics, weather, sports games, and the educational environment. For each of these applications, we form categories of possible users and the basic requirements for each of them. As a result, we identify a list of design goals that we take into consideration in developing the architecture of the library. To illustrate and validate our approach we implement a medical digital library containing actual Computed Tomography (CT) scan streams. It also contains sample medical text and audio streams to show the heterogeneity of the library. Streams are displayed in a concise, yet complete, way that makes it unproblematic for users to decide whether or not to playback a stream and to set playback options. The playback interface itself is organized in a way that accommodates synchronous and asynchronous streams and enables users to control the playback of these streams. We study the performance of the specialized search and retrieval processes in comparison to traditional search and retrieval processes. We conclude with a discussion on how to adapt the library to additional stream types in addition to suggesting other future efforts in this area.


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