Educators often inquire about the readability of books and other documents used in the classroom, with the idea that readability supports students' reading comprehension and growth. Documents used in classrooms tend to be language-based, so readability metrics have long focused on the complexity of language. However, such metrics are unsuitable for multimodal documents because these types of documents also use non-language modes of communication. This is problematic because multimodal reading is increasingly recognized as a 21st-century skill. One information theoretic solution is transinformation analysis, an approach that measures readability as the difference between the objective entropy of a document and the subjective entropy of its reader. Higher transinformation indicates more information complexity. This study explored the viability of transinformation analysis as a measure of multimodal readability. Think aloud screen recordings from 15 eighth grade "advanced readers" of Episode 2 of the born-digital novel, Inanimate Alice served as the dataset. Findings showed that 14 of the readers attended to less than half the information in the story. Mean readability was .57, indicating a complex reading experience. Readers attended to and recalled information primarily from the linguistic mode, which may have been a strategy for reducing cognitive load, or it may have reflected beliefs that reading is a language-based activity. The strong traditional readers in this study appeared to be weak at multimodal reading. In addition to its theoretical and methodological implications, the study's findings have implications for the practical need to create more opportunities for multimodal reading experiences in contemporary classrooms and libraries.

Identifying topics of a textual document is useful for many purposes. We can organize the documents by topics in digital libraries. Then, we could browse and search for the documents with specific topics. By examining the topics of a document, we can quickly understand what the document is about. To augment the traditional manual way of topic tagging tasks, which is labor-intensive, solutions using computers have been developed. This dissertation describes the design and development of a topic identification approach, in this case applied to disaster events. In a sense, this study represents the marriage of research analysis with an engineering effort in that it combines inspiration from Cognitive Informatics with a practical model from Information Retrieval. One of the design constraints, however, is that the Web was used as a universal knowledge source, which was essential in accessing the required information for inferring topics from texts. Retrieving specific information of interest from such a vast information source was achieved by querying a search engine's application programming interface. Specifically, the information gathered was processed mainly by incorporating the Vector Space Model from the Information Retrieval field. As a proof of concept, we subsequently developed and evaluated a prototype tool, Xpantrac, which is able to run in a batch mode to automatically process text documents. A user interface of Xpantrac also was constructed to support an interactive semi-automatic topic tagging application, which was subsequently assessed via a usability study. Throughout the design, development, and evaluation of these various study components, we detail how the hypotheses and research questions of this dissertation have been supported and answered. We also present that our overarching goal, which was the identification of topics in a human-comparable way without depending on a large training set or a corpus, has been achieved. / Ph. D.