2012 MU dissertations - Access restricted to UM
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Item Empirical study of image describing and searching behaviors of medical image users(University of Missouri--Columbia, 2012) Wang, Xin; Erdelez, Sanda, 1960-[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Researchers in the field of image indexing and retrieval face a crucial question -- how to design and develop efficient and effective systems that meet real users' requirements by supporting them with advanced indexing and retrieval functions and options for user interaction. According to the Mental Models Theory, designers need to reduce the dissonance between designers' conceptual models and users' mental models through developing systems that are learnable, functional and usable. There are two fundamental issues that deserve more investigations for the design of image Information Retrieval (IR) systems: Firstly, how do users represent non-textual information needs? Secondly, how do users search for images and interact with image IR to obtain non-textual materials? To address these two issues, this dissertation research carried out two studies that focused on the describing and searching behaviors of image users in a specialty area of medicine -- Radiography. The goal of this research was to discover how expert, intermediate, and novice radiological technologists represented their image information needs and searched images with different search tactics. The first study of this dissertation was to build an efficient, robust, and user-centered medical image indexing procedure. To realize this goal, it was essential to index the images at the right level of description and ensure the indexed levels match users' interest level. The first study examined 240 medical image descriptions produced by image users with different levels of domain knowledge (novices, intermediates, and experts) in the area of radiography. There are several important findings in the first study: 1) The effect of domain knowledge has been found to have a significant relationship with the use of semantic image attributes in image users' descriptions. This study found that experts employed more high-level image attributes, which require high-reasoning or diagnostic knowledge to search for a medical image (Abstract Objects and Scenes) than novices; novices were more likely to describe some basic objects that do not require high level of radiological knowledge to search for an image they need (Generic Objects) than were experts; 2) All image users preferred to use image attributes on the semantic levels to represent the image they desired to find, especially using those specific-level and scene-related attributes; 3) Image attributes generated by medical image users can be mapped to all levels of the Pyramid model that was developed to structure visual information. Therefore, the Pyramid model could be considered a robust instrument for indexing medical imagery. The second study of this dissertation focused on the use of search tactics unique to medical image information. The study was designed to address how domain knowledge interacts with search task to influence the use of search tactics and search performance of medical image searchers. The main findings of this study include: 1) Experts used significantly more search tactics (such as using more newly-generated queries, spending longer time in reading instruction (preparation for searching), browsing more screen of search results, carefully examining more enlarged images, and using more frequently limiting devices of a search engine to narrow down search results) than intermediates and novices. 2) Novices used the Re-read Instruction tactic most in order to compensate for their incapability to understand and memorize search topics. Novices also used tactics such as Examining Enlarged Images and Refine tactics least, which suggested that novices were neither unable to interpret/evaluate an image nor lack of search expertise to process their searching tasks. As a result, novices' search performance was significantly lower than both intermediates and experts. 3) Specific Tasks raised the use of a variety of search tactics comparing to General Tasks and Abstract Tasks. This is likely because medical image searchers perceive Specific Tasks as the most difficult tasks among these three types of search tasks. As a result, searchers performed worst in Specific Tasks. The findings of this study provide a series of implications for designing and evaluating the medical image information system. For instance, the results showed that medical image searchers occasionally employ Refine and Manipulations tactics during their search and interaction process. Thus, it is better to employ the faceted search interface in an image information system acting as a query refinement control. In addition, this study found that novices less frequently employ visual stimuli during the search process due to lack of domain knowledge. Image retrieval systems need to provide novices context-sensitive knowledge assistance (e.g., annotated image features). The results of the second study are beneficial for the creation of adaptive and supportive tool sets that are appropriate for different image user groups. In addition to the contributions to the design and development of image IR, this dissertation research also provided significant information to library professionals. This research revealed what intellectual parts of a medical image document the indexer or archivists should consider for representation in the indexing, so library professionals may provide better user-oriented access points to these images. Also, the knowledge about users' image searching behaviors enables medical librarians to design better training activities to help users establish more accurate and complete mental models for various image retrieval systems.Item The feasibility co-firing biomass for electricity in Missouri(University of Missouri--Columbia, 2012) Liu, Zuoming; Johnson, Thomas G.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] With the growing concerns regarding energy security, sustainability and global warming, more and more efforts have been expended to find clean, safe and renewable energy sources. Bioenergy is considered as one of the significant potential energy resources to serve as a partial replacement for fossil fuels. Use biomass as fuels to produce electricity, i.e. biopower, is one of the most popular uses of bioenergy. The main objective of this study is to investigate the feasibility co-firing biomass for electricity at the existing coal-powered plants in Missouri. A linear programming model was built to simulate the whole process of co-firing biomass in 9 selected power plants with the objective of minimizing the total cost involved in the process. Two biomass co-firing levels (10% and 15%) with three levels (10%, 20% and 30%) of biomass availability are assumed to conduct sensitivity analysis. Moreover, this study also analyzed the impact of transportation cost, resource and harvesting cost on the model's optimization outcomes. The results of the model show that co-firing biomass in those selected power plants costs more than using coal. The additional cost from co-firing biomass will decrease as the availability of biomass increases. The results from the individual plants show that the optimal capacity of biomass co-firing is about 10-15MW based on the settings of this study.Item Quantitative trait loci analysis of four components of Fusarium head blight resistance in the soft red winter wheat cultivar Truman(University of Missouri--Columbia, 2012) Islam, Md Sariful; McKendry, Anne L.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Fusarium head blight (FHB) mainly caused by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schw. (Petch)] causes devastating losses in wheat globally. Host-plant resistance provides the best hope for reducing economic losses but sources of resistance are limited. "Truman" soft red winter wheat, developed and released by the University of Missouri has excellent broad-based FHB resistance. This research was conducted to identify QTL associated with five components of resistance in Truman. Two years (2 replications per year) of phenotypic data were collected on these components of resistance on a set of 167 F9 recombinant inbred lines developed from the cross Truman/MO 94-317. Genetic linkage maps were constructed using 160 single sequence repeat and 530 diversity array technology polymorphic markers. Across years, QTL for type II resistance were identified on chromosomes 1BSc, 2BL, 2DS and 3BSc; for disease incidence on 2ASc, 2DS, and 3DS; for disease severity on 2DS, and 3BSc; for Fusarium damage kernels (FDK) on 2ASc, 2DS, and 3BLc; and for low DON on 2ASc, 2DS, and 3BLc. Additional QTL for FDK were identified on 1BLc, 2ASc, and 3BLc; and for DON on 2ASc, 2DS, and 6ALc were identified from phenotypic data collected in Kentucky. The effects of identified QTL ranged from 5.0 to 30.7 % of the total phenotypic variation. Several of these QTL appear to be potentially novel and therefore should enhance FHB resistance in programs attempting to pyramid unique FHB resistance genes through marker-assisted-selection.Item Social insecurity and the role of possessions : buying friends or replacing them?(University of Missouri--Columbia, 2012) Gunz, Alexander; Richins, Marsha Lee[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This dissertation extends the literatures on coping and social anxiety by suggesting that people cope with social threats not just by directly trying to create (and restore) social relationships, but also by indirectly coping with the psychological fallout. It suggests that they do this by seeking hedonic product benefits that can salve emotional hurt, and by seeking product benefits that affirm unrelated aspects of the self concept. Two studies with different manipulations and outcome measures show that both manipulated and chronic forms of social anxiety can give rise to any of the above coping behaviors, and shows that the pursuit of these benefits is often moderated by relevant personality variables (e.g., entity theory and values-based transformations, emotional-awareness and hedonic transformations, and materialism and extrinsic transformations). These studies largely fail to replicate past findings that self-monitoring can moderate seeking social benefits. Finally, a new study by Lee and Shrum (2012) is discovered. A reanalysis of that paper's data suggests that there may be a critical role for implicit/explicit processing in consumers' deciding whether a given coping strategy is suitable. Applying this distinction to study 2's data generates a far more close-fitting description of its data.Item Mother, father, husband, wife, soldier : identity-negotiation of veterans during re-entry into family life post-deployment(University of Missouri--Columbia, 2012) Symonds LeBlanc, Sarah E.; Olson, Loreen N.; University of Missouri-Columbia. Graduate School. Theses and Dissertations. Dissertations. 2012 Dissertations[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The purposes of this study were to (a) understand how recent military veterans negotiate their identities post-deployment, and more specifically, (b) understand how military veterans' identity negotiation impacts communication with partners and their children after war-time deployment. The current study interviewed 22 recent veterans. Using Hecht, Jackson, and Ribeau's (2003) Communication Theory of Identity (CTI) as a theoretical lens, the results revealed that participants experience the penetration of the personal, relational, and communal layers as defined by CTI. Specifically, participants had the urge to negotiate their identity post-deployment at the personal layer, fighting to go back to the person that they were before they deployed. However, as they negotiated between work and family identities, the personal layer negotiation began to interpenetrate with the communal layers as they worked to balance their work and family selves post-deployment. Then, participants learned that their work and family identities intrapenetrated within the communal layer. Next, participants' communication was affected within the relational layer as they negotiated their relational identities with their spouse and their children. Participants experienced topic avoidance, jealousy, and role negotiation with their spouse and identity gaps with their children.