The many advantages of Distributed Database (DDB) systems can only be achieved through proper DDB designs. Since designing a DDB is very difficult and expert designers are relatively few in number, "good" DDB design methodologies and associated computer-aided design tools are needed to help designers cope with design complexity and improve their productivity. Unfortunately, previous DDB design research focused on solving subproblems of data distribution design in isolation. As a result, past research on a general DDB design methodology offered only methodological frameworks that, at best, aggregate a set of non-integrated design techniques. The conventional separation of logical design from fragmentation design is problematic, but has not been fully analyzed. This dissertation presents the SEER-DTS methodology developed for the purposes of overcoming the methodological inadequacies of conventional design methodologies, resolving the DDB design problem in an integrated manner and facilitating design automation. It is based on a static semantic data model, SEER (Synthesized Extended Entity-Relationship Model) and a dynamic data model, DTS (Distributed Transaction Scheme), which together provide complete and consistent modeling mechanisms for acquiring/representing DDB design inputs and facilitating DDB schema design. In this methodology, requirement/distribution analysis and conceptual design are integrated and logical and fragmentation designs are combined. "Semantics-based" design techniques have been developed to allow for end-user design specifications and seamless design schema transformations, thereby simplifying design tasks. Towards our ultimate goal of design automation, an architectural framework for a computer-aided DDB design system, Auto-DDB, was formulated and the system was prototyped. As part of the developmental effort, a real-world DDB design case study was conducted to verify the applicability of the SEER-DTS methodology in a manual design mode. The results of a laboratory experiment showed that the SEER-DTS methodology produced better design outcomes (in terms of design effectiveness and efficiency) than a Conventional Best methodology performed by non-expert designers in an automated design mode. However, no statistically significant difference was found in user-perceived ease of use.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 97-103). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--University of Florida, 2002. / Title from title page of source document. Includes vita. Includes bibliographical references.

Data replication is a key building block for large-scale distributed systems to improve availability, performance, and scalability. Because there is a fundamental trade-off between performance and consistency as well as between availability and consistency, systems must make trade-offs among these factors based on the demands and technologies of their target environments and workloads. Unfortunately, existing replication protocols and mechanisms are intrinsically entangled with specific policy assumptions. Therefore, to accommodate new trade-offs for new policy requirements, developers have to either build a new replication system from scratch or modify existing mechanisms. This dissertation presents a universal data replication architecture (URA) that cleanly separates mechanism and policy and supports Partial Replication (PR), Any Consistency (AC), and Topology Independence (TI) simultaneously. Our architecture yields two significant advantages. First, by providing a single set of mechanisms that capture the common underlying abstractions for data replication, URA can serve as a common substrate for building and deploying new replication systems. It therefore can significantly reduce the effort required to construct or modify a replication system. Second, by providing a set of general and flexible mechanisms independent of any specific policy, URA enables better trade-offs than any current system can provide. In particular, URA can simultaneously provide the three PRACTI properties while any existing system can provide at most two of them. Our experimental results and case-study systems confirm that universal data replication architecture is a way to build better replication systems and a better way to build replication systems. / text

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Thesis (Ph.D.)--University of Melbourne, Dept. of Computer Science and Software Engineering, 2006. / Typescript. Includes bibliographical references (leaves 189-207).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 1992. / Includes bibliographical references (leaves 116-119). Available online via OhioLINK's ETD Center.

Thesis (M.S.)--Brigham Young University. Dept. of Technology, 2005. / Includes bibliographical references (p. 95-97).

M.Com. (Computer Auditing) / Please refer to full text to view abstract