Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: XML, Query Re-Writing, View Maintenance, Query Containment. Includes bibliographical references. (p.108-111)

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 97-100).

This project is concerned with the development of a search algorithm for a large archival database. The Port Elizabeth Genealogical Information System (PEGIS) contains a database consisting of almost 600000 individuals. The standard search algorithms are no longer sufficient to locate individuals in the database. A new algorithm was required that allows searches on any of the words or dates in the database, as well as a means to specify where in the desired record a word should occur. A ranking function of retrieved records was also required. A literature study on the field of Information Retrieval and on algorithms designed specifically for the PEGIS was done. These algorithms were adapted and hybridized to yield a search algorithm that allows for the boolean formulation of queries and the specification of the structure of search words in the desired records. The algorithm ranks retrieved records in assumed relevance to the user. The new algorithms were evaluated with regards to retrieval speed and accuracy and were found to be very effective.

M.Bibl. / Please refer to full text to view abstract

Object oriented databases have been gaining popularity over the years. Their ease of use and the advantages that they offer over relational databases have made them a popular choice amongst database administrators. Their use in previous years was restricted to business and administrative applications, but improvements in technology and the emergence of new, data-intensive applications has led to the increase in the use of object databases. This study investigates four Open Source object-oriented databases on their ability to carry out the standard database operations of storing, querying, updating and deleting database objects. Each of these databases will be timed in order to measure which is capable of performing a particular function faster than the other.

The Internet and networks in general have become essential tools for disseminating in-formation. Search engines have become the predominant means of finding information on the Web and all other data repositories, including local resources. Domain scientists regularly acquire and analyze images generated by equipment such as microscopes and cameras, resulting in complex image files that need to be managed in a convenient manner. This type of integrated environment has been recently termed a netcentric sci-entific research repository. I developed a number of data manipulation tools that allow researchers to manage their information more effectively in a netcentric environment. The specific contributions are: (1) A unique interface for management of data including files and relational databases. A wrapper for relational databases was developed so that the data can be indexed and searched using traditional search engines. This approach allows data in databases to be searched with the same interface as other data. Fur-thermore, this approach makes it easier for scientists to work with their data if they are not familiar with SQL. (2) A Web services based architecture for integrating analysis op-erations into a repository. This technique allows the system to leverage the large num-ber of existing tools by wrapping them with a Web service and registering the service with the repository. Metadata associated with Web services was enhanced to allow this feature to be included. In addition, an improved binary to text encoding scheme was de-veloped to reduce the size overhead for sending large scientific data files via XML mes-sages used in Web services. (3) Integrated image analysis operations with SQL. This technique allows for images to be stored and managed conveniently in a relational da-tabase. SQL supplemented with map algebra operations is used to select and perform operations on sets of images.

Medical educators advocate the need for medical students to acquire information management skills, including the ability to search the MEDLINE database. There has been no published validated method available to use for assessing medical students' MEDLINE information retrieval skills. This research proposes and evaluates a method, designed as the MEDLINE Metric, for assessing medical students' search skills. MEDLINE Metric consists of: (a) the development, by experts, of realistic clinical scenarios that include highly constructed search questions designed to test defined search skills; (b) timed tasks (searches) completed by subjects; (c) the evaluation of search results; and (d) instructive feedback. A goal is to offer medical educators a valid, reliable, and feasible way to judge mastery of information searching skill by measuring results (search retrieval) rather than process (search behavior) or cognition (knowledge about searching). Following a documented procedure for test development, search specialists and medical content experts formulated six clinical search scenarios and questions. One hundred and forty-five subjects completed the six-item test under timed conditions. Subjects represented a wide range of MEDLINE search expertise. One hundred twenty complete cases were used, representing 53 second-year medical students (44%), 47 fourth-year medical students (39%), and 20 medical librarians (17%). Data related to educational level, search training, search experience, confidence in retrieval, difficulty of search, and score were analyzed. Evidence supporting the validity of the method includes the agreement by experts about the skills and knowledge necessary to successfully retrieve information relevant to a clinical question from the MEDLINE database. Also, the test discriminated among different performance levels. There were statistically significant, positive relationships between test score and level of education, self-reported previous MEDLINE training, and self-reported previous search experience. The findings from this study suggest that MEDLINE Metric is a valid method for constructing and administering a performance-based test to identify mastery in searching the MEDLINE database. The test's reliability needs to be established.

This study reports changes in online database searching at North Texas State University when equipment speed was increased. Data were from database vendor invoices and price and sale data of online equipment. The hypotheses examined the relationship between the decrease in the cost of online equipment and the change to faster online equipment and the change in the number of databases that changed for online types. The change in equipment was related to changes in the number of offline prints per hour, the average time per search, the average number of descriptors per search, the number of searches per month, and the rank order of database use over the studied period. The increase in the number of databases with billed types was related to the number of online billed types produced. The number of prints was related to the number of billed types. Time spent online was examined for annual seasonal cycles. The major statistical tool was time-series analysis, although other methods were applied.

In recent years XML, the eXtensible Markup Language has become the de-facto standard for publishing and exchanging information on the web and in enterprise data integration systems. Materialized views are often used in information integration systems to present a unified schema for efficient querying of distributed and possibly heterogenous data sources. On similar lines, ACE-XQ, an XQuery based semantic caching system shows the significant performance gains achieved by caching query results (as materialized views) and using these materialized views along with query containment techniques for answering future queries over distributed XML data sources. To keep data in these materialized views of ACE-XQ up-to-date, the view must be maintained i.e. whenever the base data changes, the corresponding cached data in the materialized view must also be updated. This thesis builds on the query containment ideas of ACE-XQ and proposes an efficient approach for self-maintenance of materialized views. Our experimental results illustrate the significant performance improvement achieved by this strategy over view re-computation for a variety of situations.

The purpose of this thesis is to identify and quantify the information clues found in the document representations in the World Wide Web environment. This study uses three topics to find document representations: custom publishing, distance education, and tactile graphics. Four Web search engines are used: AltaVista, InfoSeek Ultra, Lycos, and Open Text Index. The findings of the random sample show that the search engines produce little duplication in their display of the results. Just over half of the cases reveal information clues about the document's authorship, origin, format or subject. The summary field shows the highest number of information clues. The title and Uniform Resource Locator fields do not contain many information clues. Few of the fields contain clues about the authorship of the documents. Topical relevance is questionable in many of the cases. The study recommends further research on the comparison of search engines, on the study of searches on the Web for commercial, academic and personal topics, and on information seeking behaviors relating to Web searching. Recommendations are made for Web training and Web page design to assist users in finding relevant information more quickly.