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USER-CENTERED VIRTUAL ENVIRONMENT ASSESSMENT AND DESIGN FOR COGNITIVE REHABILITATION APPLICATIONS
Title
USER-CENTERED VIRTUAL ENVIRONMENT ASSESSMENT AND DESIGN FOR COGNITIVE REHABILITATION APPLICATIONS.
Creator
Fidopiastis, Cali, Rolland, Jannick, University of Central Florida
Abstract / Description
Virtual environment (VE) design for cognitive rehabilitation necessitates a new methodology to ensure the validity of the resulting rehabilitation assessment. We propose that benchmarking the VE system technology utilizing a user-centered approach should precede the VE construction. Further, user performance baselines should be measured throughout testing as a control for adaptive effects that may confound the metrics chosen to evaluate the rehabilitation treatment. To support these claims we...
Show moreVirtual environment (VE) design for cognitive rehabilitation necessitates a new methodology to ensure the validity of the resulting rehabilitation assessment. We propose that benchmarking the VE system technology utilizing a user-centered approach should precede the VE construction. Further, user performance baselines should be measured throughout testing as a control for adaptive effects that may confound the metrics chosen to evaluate the rehabilitation treatment. To support these claims we present data obtained from two modules of a user-centered head-mounted display (HMD) assessment battery, specifically resolution visual acuity and stereoacuity. Resolution visual acuity and stereoacuity assessments provide information about the image quality achieved by an HMD based upon its unique system parameters. When applying a user-centered approach, we were able to quantify limitations in the VE system components (e.g., low microdisplay resolution) and separately point to user characteristics (e.g., changes in dark focus) that may introduce error in the evaluation of VE based rehabilitation protocols. Based on these results, we provide guidelines for calibrating and benchmarking HMDs. In addition, we discuss potential extensions of the assessment to address higher level usability issues. We intend to test the proposed framework within the Human Experience Modeler (HEM), a testbed created at the University of Central Florida to evaluate technologies that may enhance cognitive rehabilitation effectiveness. Preliminary results of a feasibility pilot study conducted with a memory impaired participant showed that the HEM provides the control and repeatability needed to conduct such technology comparisons. Further, the HEM affords the opportunity to integrate new brain imaging technologies (i.e., functional Near Infrared Imaging) to evaluate brain plasticity associated with VE based cognitive rehabilitation.
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Date Issued
2006
Identifier
CFE0001203, ucf:46946
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001203
Perceptual Judgment: The Impact of Image Complexity and Training Method on Category Learning
Title
Perceptual Judgment: The Impact of Image Complexity and Training Method on Category Learning.
Creator
Curtis, Michael, Jentsch, Florian, Salas, Eduardo, Szalma, James, Boloni, Ladislau, University of Central Florida
Abstract / Description
The goal of this dissertation was to bridge the gap between perceptual learning theory and training application. Visual perceptual skill has been a vexing topic in training science for decades. In complex task domains, from aviation to medicine, visual perception is critical to task success. Despite this, little, if any, emphasis is dedicated to developing perceptual skills through training. Much of this may be attributed to the perceived inefficiency of perceptual training. Recent applied...
Show moreThe goal of this dissertation was to bridge the gap between perceptual learning theory and training application. Visual perceptual skill has been a vexing topic in training science for decades. In complex task domains, from aviation to medicine, visual perception is critical to task success. Despite this, little, if any, emphasis is dedicated to developing perceptual skills through training. Much of this may be attributed to the perceived inefficiency of perceptual training. Recent applied research in perceptual training with discrimination training, however, holds promise for improved perceptual training efficiency. As with all applied research, it is important to root application in solid theoretical bases. In perceptual learning, the challenge is connecting the basic science to more complex task environments. Using a common aviation task as an applied context, participants were assigned to a perceptual training condition based on variation of image complexity and training type. Following the training, participants were tested for transfer of skill. This was intended to help to ground a potentially useful method of perceptual training in a model category learning, while offering qualitative testing of model fit in increasingly complex visual environments. Two hundred and thirty-one participants completed the computer based training module. Results indicate that predictions of a model of category learning largely extend into more complex training stimuli, suggesting utility of the model in more applied contexts. Although both training method conditions showed improvement across training blocks, the discrimination training condition did not transfer to the post training transfer tasks. Lack of adequate contextual information related to the transfer task in training was attributed to this outcome. Further analysis of the exposure training condition showed that individuals training with simple stimuli performed as well as individuals training on more complex stimuli in a complex transfer task. On the other hand, individuals in the more complex training conditions were less accurate when presented with a simpler representation of the task in transfer. This suggests training benefit to isolating essential task cues from irrelevant information in perceptual judgment tasks. In all, the study provided an informative look at both the theory and application associated with perceptual category learning. Ultimately, this research can help inform future research and training development in domains where perceptual judgment is critical for success.
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Date Issued
2011
Identifier
CFE0004096, ucf:49139
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004096
Visuo-spatial abilities in remote perception: A meta-analysis of empirical work
Title
Visuo-spatial abilities in remote perception: A meta-analysis of empirical work.
Creator
Fincannon, Thomas, Jentsch, Florian, Sims, Valerie, Bowers, Clint, Chen, Jessie, University of Central Florida
Abstract / Description
Meta-analysis was used to investigate the relationship between visuo-spatial ability and performance in remote environments. In order to be included, each study needed to examine the relationship between the use of an ego-centric perspective and various dimensions of performance (i.e., identification, localization, navigation, and mission completion time). The moderator analysis investigated relationships involving: (a) visuo-spatial construct with an emphasis on Carroll's (1993)...
Show moreMeta-analysis was used to investigate the relationship between visuo-spatial ability and performance in remote environments. In order to be included, each study needed to examine the relationship between the use of an ego-centric perspective and various dimensions of performance (i.e., identification, localization, navigation, and mission completion time). The moderator analysis investigated relationships involving: (a) visuo-spatial construct with an emphasis on Carroll's (1993) visualization (VZ) factor; (b) performance outcome (i.e., identification, localization, navigation, and mission completion time); (c) autonomy to support mission performance; (d) task type (i.e., navigation vs. reconnaissance); and (e) experimental testbed (i.e., physical vs. virtual environments). The process of searching and screening for published and unpublished analyses identified 81 works of interest that were found to represent 50 unique datasets. 518 effects were extracted from these datasets for analyses.Analyses of aggregated effects (Hunter (&) Schmidt, 2004) found that visuo-spatial abilities were significantly associated with each construct, such that effect sizes ranged from weak (r = .235) to moderately strong (r = .371). For meta-regression (Borenstein, Hedges, Figgins, (&) Rothstein, 2009; Kalaian (&) Raudenbush, 1996; Tabachnick (&) Fidell, 2007), moderation by visuo-spatial construct (i.e., focusing on visualization) was consistently supported for all outcomes. For at least one of the outcomes, support was found for moderation by test, the reliability coefficient of a test, autonomy (i.e. to support identification, localization, and navigation), testbed (i.e., physical vs. virtual environment), intended domain of application, and gender. These findings illustrate that majority of what researchers refer to as (")spatial ability(") actually uses measures that load onto Carroll's (1993) visualization (VZ) factor. The associations between this predictor and all performance outcomes were significant, but the significant variation across moderators highlight important issues for the design of unmanned systems and the external validity of findings across domains. For example, higher levels of autonomy for supporting navigation decreased the association between visualization (VZ) and performance. In contrast, higher levels of autonomy for supporting identification and localization increased the association between visualization (VZ) and performance. Furthermore, moderation by testbed, intended domain of application, and gender challenged the degree to which findings can be expected to generalize across domains and sets of participants.
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Date Issued
2013
Identifier
CFE0004680, ucf:49858
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004680
A Psychophysical Approach to Standardizing Texture Compression for Virtual Environments
Title
A Psychophysical Approach to Standardizing Texture Compression for Virtual Environments.
Creator
Flynn, Jeremy, Szalma, James, Fidopiastis, Cali, Jentsch, Florian, Shah, Mubarak, University of Central Florida
Abstract / Description
Image compression is a technique to reduce overall data size, but its effects on human perception have not been clearly established. The purpose of this effort was to determine the most effective psychophysical method for subjective image quality assessment, and to apply those findings to an objective algorithm. This algorithm was used to identify the minimum level of texture compression noticeable to the human, in order to determine whether compression-induced texture distortion impacted...
Show moreImage compression is a technique to reduce overall data size, but its effects on human perception have not been clearly established. The purpose of this effort was to determine the most effective psychophysical method for subjective image quality assessment, and to apply those findings to an objective algorithm. This algorithm was used to identify the minimum level of texture compression noticeable to the human, in order to determine whether compression-induced texture distortion impacted game-play outcomes. Four experiments tested several hypotheses. The first hypothesis evaluated which of three magnitude estimation (ME) methods (absolute ME, absolute ME plus, or ME with a standard) for image quality assessment was the most reliable. The just noticeable difference (JND) point for textures compression against the Feature Similarity Index for color was determined The second hypothesis tested whether human participants perceived the same amount of distortion differently when textures were presented in three ways: when textures were displayed as flat images; when textures were wrapped around a model; and when textures were wrapped around models and in a virtual environment. The last set of hypotheses examined whether compression affected both subjective (immersion, technology acceptance, usability) and objective (performance) gameplay outcomes. The results were: the absolute magnitude estimation method was the most reliable; no difference was observed in the JND threshold between flat textures and textures placed on models, but textured embedded within the virtual environment were more noticeable than in the other two presentation formats. There were no differences in subjective gameplay outcomes when textures were compressed to below the JND thresholds; and those who played a game with uncompressed textures performed better on in-game tasks than those with the textures compressed, but only on the first in-game day. Practitioners and researchers can use these findings to guide their approaches to texture compression and experimental design.
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Date Issued
2018
Identifier
CFE0007178, ucf:52250
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007178
Infectious Disease Risks in Developing Countries: A Non-Market Valuation Exercise
Title
Infectious Disease Risks in Developing Countries: A Non-Market Valuation Exercise.
Creator
Samajpati, Shreejata, Gerking, Shelby, Dickie, Mark, Caputo, Michael, Roy, Joyashree, University of Central Florida
Abstract / Description
This dissertation focuses on the non-market valuation of health-risks of malaria, an infectious disease that imposes a substantive public health burden across the globe, hitting particularly hard the tropical developing nations of Africa and Asia. The United Nations Millennium Development Goals include malaria control as a priority and large investments are underway to promote effective prevention and treatment. Despite such concerted supply-side efforts, malaria-related mortality and...
Show moreThis dissertation focuses on the non-market valuation of health-risks of malaria, an infectious disease that imposes a substantive public health burden across the globe, hitting particularly hard the tropical developing nations of Africa and Asia. The United Nations Millennium Development Goals include malaria control as a priority and large investments are underway to promote effective prevention and treatment. Despite such concerted supply-side efforts, malaria-related mortality and morbidity still abound due to a complex interface of factors like climate-change, poverty, inadequate control behavior, infection and prevention externalities, parasite resistance etc. This research project digs into the demand-side of the health problem, considers the "externality" dimension to prevention, and primarily asks the question: how do individuals in developing countries view competing disease-control (prevention) measures, viz. a publicly-administered community-level malaria control measure as against private preventive choices. A theoretical model is developed to help explore the public-private interplay of health risks of malaria. The malaria-endemic regions of Kolkata (India) and its rural fringes comprise the site for an empirical investigation. A field survey (Malaria Risk and Prevention Survey, October-December, 2011) incorporating a mix of stated and revealed preference techniques of health valuation is implemented. Risk-perceptions of respondents are elicited using a measurable visual-aid and individuals' perceived valuations of health-risk reductions, randomly offered with the public and private health treatments, are empirically ascertained. Using a Likelihood Ratio Test on the structural risk parameters, it is seen that individuals' valuations of health risk reductions are the same across the private and public treatments. The comparative valuation exercise, thus, corroborates the externality dimension to malaria control, calling for greater public action to combat malaria. The viability of such a scaled-up public malaria program, in the context of Kolkata, is discussed by comparing the public treatment willingness to pay estimates with the annual estimated costs that the Kolkata Municipal Corporation, the civic body in the city of Kolkata, maintains on account of vector control. Results from the comparative valuation exercises also support the idea that private prevention is generally responsive to prevention costs, indicating the importance of price incentives to induce greater prevention. The issues of health valuation and price sensitivity are further explored across various split-samples differentiated on the basis of socio-economic attributes, disease exposure, actual prevention efforts and perceived malaria risks of survey respondents. Such auxiliary exercises help analyze the valuation question in greater depth, and generate policy insights into the potential factors that shape private prevention behavior.
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Date Issued
2012
Identifier
CFE0004594, ucf:49195
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004594