Yanpu Zhang

Date of Award


Document Type


Degree Name

Master of Science (MS)


Computer Science

First Advisor

Dr. Zhengxin Chen


Among the challenges of multimedia computing and mobile computing, a mechanism for data retrieval in multimedia databases under wireless mobile environments seems to be the most difficult issue. The problem is that sizes of images in a multimedia DBMS queried by mobile clients through wireless networks are different and unpredictable. Current Quality of Service (QoS) framework has no answer for it because all the QoS principles are based on users’ pre-requirements. However, the issue is that in multimedia applications, it is difficult to know the size of targeted retrieval object. There should be new mechanism of QoS to participate in query processing and provide an efficient theme around which mobile multimedia database applications can b practicably realized. In this thesis we focus on extending QoS management in wireless mobile environments to specify a range of acceptable QoS for multimedia query processing rather than trying either to guarantee specific values or to stop the querying. Through the investigation of current research approaches, we conclude that the statistical or empirical resource utilizations in query processing are the dominant methods to solve the problems. All proposals choose stopping query if the required QoS conditions can not meet the related statistical or empirical resources utilizations. To address QoS in mobile multimedia DBMS issues, we explore an approach to execute query processing based on real time QoS conditions all coming from client, network, and server. We propose a QoS-based matrix to support query processing of object-relational multimedia databases in the context of wireless mobile environments. The proposed QoS-based Querying Processing Precision Matrix (QQPPM) is based on (1) real-time QoS conditions in wireless networks; (2) multimedia database’s object properties; and (3) Mobile client-site data processing capability. We study related technologies as the foundations to support multimedia query processing in wireless mobile environments. Moreover, we conduct OPNET simulations, and the results indicate that our assumption is reasonable and practicable.


A Thesis Presented to the Department of Computer Science and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Master of Science University of Nebraska at Omaha. Copyright 2004 Yanpu Zhang

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