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UNT Scholarly Works
- Access to Film and Video Works: Surrogates for Moving Image Documents
- This doctoral dissertation discusses access to film and video works. Physical and intellectual access to moving image documents is insufficient, often insignificant, at the level of the individual user. Existing access tools suffer from a lack of recognition of the differences between linguistic text communication and image communication. Browsing and relevance judgements are made difficult by the physical realities of film and video documents - one cannot flip through them - and by the habits of serial and passive viewing. digital.library.unt.edu/ark:/67531/metadc77222/
- Collection-Level Subject Access in Aggregations of Digital Collections: Metadata Application and Use
- This doctoral dissertation is about collection-level subject access in aggregations of digital collections. Abstract: Problems in subject access to information organization systems have been under investigation for a long time. Focusing on item-level information discovery and access, researchers have identified a range of subject access problems, including quality and application of metadata, as well as the complexity of user knowledge required for successful subject exploration. While aggregations of digital collections built in the United States and abroad generate collection-level metadata of various levels of granularity and richness, no research has yet focused on the role of collection-level metadata in user interaction with these aggregations. This dissertation research sought to bridge this gap by answering the question "How does collection-level metadata mediate scholarly subject access to aggregated digital collections?" This goal was achieved using three research methods: - in-depth comparative content analysis of collection-level metadata in three large-scale aggregations of cultural heritage digital collections: Opening History, American Memory, and The European Library, - transaction log analysis of user interactions, with Opening History, and - interview and observation data on academic historians interacting with two aggregations: Opening History and American Memory. It was found that subject-based resource discovery is significantly influenced by collection-level metadata richness. The richness includes such components as: 1) describing collection's subject matter with mutually-complementary values in different metadata fields, and 2) a variety of collection properties/characteristics encoded in the free-text Description field, including types and genres of objects in a digital collection, as well as topical, geographic and temporal coverage are the most consistently represented collection characteristics in free-text Description fields. Analysis of user interactions with aggregations of digital collections yields a number of interesting findings. Item-level user interactions were found to occur more often than collection-level interactions. Collection browse is initiated more often than search, while subject browse (topical and geographic) is used most often. Majority of collection search queries fall within FRBR Group 3 categories: object, concept, and place. Significantly more object, concept, and corporate body searches and less individual person, event and class of personas searches were observed in collection searches than in item searches. While collection search is most often satisfied by Description and/or Subjects collection metadata fields, it would not retrieve a significant proportion of collection records without controlled-vocabulary subject metadata (Temporal Coverage, Geographic Coverage, Subjects, and Objects), and free-text metadata (the Description field). Observation data shows that collection metadata records in Opening History and American Memory aggregations are often viewed. Transaction log data show a high level of engagement with collection metadata records in Opening History, with the total page views for collections more than 4 times greater than item page views. Scholars observed viewing collection records valued descriptive information on provenance, collection size, types of objects, subjects, geographic coverage, and temporal coverage information. They also considered the structured display of collection metadata in Opening History more useful than the alternative approach taken by other aggregations, such as American Memory, which displays only the free-text Description field to the end-user. The results extend the understanding of the value of collection-level subject metadata, particularly free-text metadata, for the scholarly users of aggregations of digital collections. The analysis of the collection metadata created by three large-scale aggregations provides a better understanding of collection-level metadata application patterns and suggests best practices. This dissertation is also the first empirical research contribution to test the FRBR model as a conceptual and analytic framework for studying collection-level subject access. digital.library.unt.edu/ark:/67531/metadc67618/
- Secure execution environments through reconfigurable lightweight cryptographic components
- This doctoral dissertation discusses secure execution environments through reconfigurable lightweight cryptographic components. Software protection is one of the most important problems in the area of computing as it affects a multitude of players like software vendors, digital content providers, users, and government agencies. There are multiple dimensions to this broad problem of software protection. The most important ones are: 1) protecting software from reverse engineering. 2) protecting software from tamper (or modification). 3) preventing software piracy. 4) verification of integrity of the software. In this thesis the authors focus on these areas of software protection. The basic requirement to achieve these goals is to provide a secure execution environment, which ensures that the programs behave in the same way as it was designed, and the execution platforms respect certain types of wishes specified by the program. The authors take the approach of providing secure execution environment through architecture support. The authors exploit the power of reconfigurable components in achieving this. The first problem the authors consider is to provide architecture support for obfuscation. This also achieves the goals of tamper resistance, copy protection, and IP protection indirectly. The authors' approach is based on the intuition that the software is a sequence of instructions (and data) and if the sequence as well the contents are obfuscated then all the required goals can be achieved. The second problem the authors solve is integrity verification of the software particularly in embedded devices. The authors' solution is based on the intuition that an obfuscated (permuted) binary image without any dynamic traces reveals very little information about the IP of the program. Moreover, if this obfuscation function becomes a shared secret between the verifier and the embedded device then verification can be performed in a trustworthy manner. Cryptographic components form the underlying building blocks/primitives of any secure execution environment. The authors use of reconfigurable components to provide software protection in both Arc3D and TIVA led us to an interesting observation about the power of reconfigurable components. Reconfigurable components provide the ability to use the secret (or key) in a much stronger way than the convention cryptographic designs. This opened up an opportunity for us to explore the use of reconfigurable gates to build cryptographic functions. digital.library.unt.edu/ark:/67531/metadc96840/