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INVESTIGATION OF VISUAL REQUIREMENTS FOR CHANGE DETECTION
Title
INVESTIGATION OF VISUAL REQUIREMENTS FOR CHANGE DETECTION.
Creator
Niederman, Elisabeth, Hancock, Peter, University of Central Florida
Abstract / Description
In this study, participants performed a change detection task. Specifically we examined whether participants had to fixate on a difference between two images before they could detect it. Thirty-six participants performed a change detection task in either a 3 minute or a 1.5 minute condition. We found a significant interaction between task duration and fixation type (whether the participant had fixated on the difference in both, one, or neither image). Participants found a greater number of...
Show moreIn this study, participants performed a change detection task. Specifically we examined whether participants had to fixate on a difference between two images before they could detect it. Thirty-six participants performed a change detection task in either a 3 minute or a 1.5 minute condition. We found a significant interaction between task duration and fixation type (whether the participant had fixated on the difference in both, one, or neither image). Participants found a greater number of differences given more time only when they fixated on the difference in both images. The number of differences which were detected by participants with a fixation on only one image or on neither image did not increase with a corresponding increase in time, indicating that some mechanical error may be involved. This suggests that participants need to fixate on a difference before being able to detect it.
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Date Issued
2013
Identifier
CFH0004500, ucf:45152
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004500
THERMAL DETECTION OF BIOMARKERS USING PHASE CHANGE NANOPARTICLES
Title
THERMAL DETECTION OF BIOMARKERS USING PHASE CHANGE NANOPARTICLES.
Creator
Wang, Chaoming, Su, Ming, University of Central Florida
Abstract / Description
Most of existing techniques cannot be used to detect molecular biomarkers (i.e., protein and DNA) contained in complex body fluids due to issues such as enzyme inhibition or signal interference. This thesis describes a nanoparticle-based thermal detection method for the highly sensitive detections of multiple DNA biomarkers or proteins contained in different type of fluids such as buffer solution, cell lysate and milk by using solid-liquid phase change nanoparticles as thermal barcodes....
Show moreMost of existing techniques cannot be used to detect molecular biomarkers (i.e., protein and DNA) contained in complex body fluids due to issues such as enzyme inhibition or signal interference. This thesis describes a nanoparticle-based thermal detection method for the highly sensitive detections of multiple DNA biomarkers or proteins contained in different type of fluids such as buffer solution, cell lysate and milk by using solid-liquid phase change nanoparticles as thermal barcodes. Besides, this method has also been applied for thrombin detection by using RNA aptamer-functionalized phase change nanoparticles as thermal probes. Furthermore, using nanostructured Si surface that have higher specific area can enhance the detection sensitivity by four times compared to use flat aluminum surfaces. The detection is based on the principle that the temperature of solid will not rise above its melting temperature unless all solid is molten, thus nanoparticles will have sharp melting peak during a linear thermal scan process. A one-to-one correspondence can be created between one type of nanoparticles and one type of biomarker, and multiple biomarkers can be detected simultaneously using different type nanoparticles. The melting temperature and the heat flow reflect the type and the concentration of biomarker, respectively. The melting temperatures of nanoparticles are designed to be over 100°C to avoid interference from species contained in fluids. The use of thermal nanoparticles allows detection of multiple low concentration DNAs or proteins in a complex fluid such as cell lysate regardless of the color, salt concentration, and conductivity of the sample.
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Date Issued
2010
Identifier
CFE0003330, ucf:48473
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003330
PERCEPTUAL GROUPING BY CLOSURE IN VISUAL WORKING MEMORY
Title
PERCEPTUAL GROUPING BY CLOSURE IN VISUAL WORKING MEMORY.
Creator
Neira, Sofia, Neider, Mark, University of Central Florida
Abstract / Description
Research on visual working memory (VWM) suggests a capacity limit of three to four objects (Luck & Vogel, 1997), but recent studies on the fidelity of VWM capacity for objects indicates that informational bandwidth, which can vary with factors like complexity and amenability to perceptual grouping, can interact with this capacity (Brady, Konkle & Alvarez, 2011). For example, individual features can be grouped into objects for an added benefit in VWM capacity (Xu, 2002). Along these lines, the...
Show moreResearch on visual working memory (VWM) suggests a capacity limit of three to four objects (Luck & Vogel, 1997), but recent studies on the fidelity of VWM capacity for objects indicates that informational bandwidth, which can vary with factors like complexity and amenability to perceptual grouping, can interact with this capacity (Brady, Konkle & Alvarez, 2011). For example, individual features can be grouped into objects for an added benefit in VWM capacity (Xu, 2002). Along these lines, the Gestalt principles of proximity and connectedness have been shown to benefit VWM, although they do not influence capacity equally (Xu 2006; Woodman, Vecera & Luck, 2003). Closure, which has not been investigated for its influence in VWM capacity, is similar to connectedness and proximity as it promotes the perception of a coherent object without physical connections. In the current experiment, we evaluated whether closure produces similar or greater VWM capacity advantages compared to proximity by having participants engage in a change detection task. Four L-shaped features were grouped in tilted clusters to either form an object (closure condition) or not (no-object condition), with a set size of two (8 L features), four (16 L features), or six clusters (24 L features). Following a brief mask (1000 ms), the orientation of one cluster was changed (tilted 25 or -25 degrees) on half the trials. Our results indicate that there was no difference in accuracy or reaction time for the perceptual grouping conditions of closure/no-object, although we did find a main effect for set size and change conditions. Overall, it seems that grouping by closure provides no further advantages to VWM capacity than proximity; however, more experiments need to be conducted to solidify the findings of the current experiment.
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Date Issued
2016
Identifier
CFH2000038, ucf:45604
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000038
COMPRESSIVE AND CODED CHANGE DETECTION: THEORY AND APPLICATION TO STRUCTURAL HEALTH MONITORING
Title
COMPRESSIVE AND CODED CHANGE DETECTION: THEORY AND APPLICATION TO STRUCTURAL HEALTH MONITORING.
Creator
Sarayanibafghi, Omid, Atia, George, Vosoughi, Azadeh, Rahnavard, Nazanin, University of Central Florida
Abstract / Description
In traditional sparse recovery problems, the goal is to identify the support of compressible signals using a small number of measurements. In contrast, in this thesis the problem of identification of a sparse number of statistical changes in stochastic phenomena is considered when decision makers only have access to compressed measurements, i.e., each measurement is derived by a subset of features. Herein, we propose a new framework that is termed Compressed Change Detection. The main...
Show moreIn traditional sparse recovery problems, the goal is to identify the support of compressible signals using a small number of measurements. In contrast, in this thesis the problem of identification of a sparse number of statistical changes in stochastic phenomena is considered when decision makers only have access to compressed measurements, i.e., each measurement is derived by a subset of features. Herein, we propose a new framework that is termed Compressed Change Detection. The main approach relies on integrating ideas from the theory of identifying codes with change point detection in sequential analysis. If the stochastic properties of certain features change, then the changes can be detected by examining the covering set of an identifying code of measurements. In particular, given a large number N of features, the goal is to detect a small set of features that undergoes a statistical change using a small number of measurements. Sufficient conditions are derived for the probability of false alarm and isolation to approach zero in the asymptotic regime where N is large.As an application of compressed change detection, the problem of detection of a sparse number of damages in a structure for Structural Health Monitoring (SHM) is considered. Since only a small number of damage scenarios can occur simultaneously, change detection is applied to responses of pairs of sensors that form an identifying code over a learned damage-sensing graph. Generalizations of the proposed framework with multiple concurrent changes and for arbitrary graph topologies are presented.
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Date Issued
2016
Identifier
CFE0006387, ucf:51507
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006387
Investigating the universality and comprehensive ability of measures to assess the state of workload
Title
Investigating the universality and comprehensive ability of measures to assess the state of workload.
Creator
Abich, Julian, Reinerman, Lauren, Lackey, Stephanie, Szalma, James, Taylor, Grant, University of Central Florida
Abstract / Description
Measures of workload have been developed on the basis of the various definitions, some are designed to capture the multi-dimensional aspects of a unitary resource pool (Kahneman, 1973) while others are developed on the basis of multiple resource theory (Wickens, 2002). Although many theory based workload measures exist, others have often been constructed to serve the purpose of specific experimental tasks. As a result, it is likely that not every workload measure is reliable and valid for all...
Show moreMeasures of workload have been developed on the basis of the various definitions, some are designed to capture the multi-dimensional aspects of a unitary resource pool (Kahneman, 1973) while others are developed on the basis of multiple resource theory (Wickens, 2002). Although many theory based workload measures exist, others have often been constructed to serve the purpose of specific experimental tasks. As a result, it is likely that not every workload measure is reliable and valid for all tasks, much less each domain. To date, no single measure, systematically tested across experimental tasks, domains, and other measures is considered a universal measure of workload. Most researchers would argue that multiple measures from various categories should be applied to a given task to comprehensively assess workload. The goal for Study 1 to establish task load manipulations for two theoretically different tasks that induce distinct levels of workload assessed by both subjective and performance measures was successful. The results of the subjective responses support standardization and validation of the tasks and demands of that task for investigating workload. After investigating the use of subjective and objective measures of workload to identify a universal and comprehensive measure or set of measures, based on Study 2, it can only be concluded that not one or a set of measures exists. Arguably, it is not to say that one will never be conceived and developed, but at this time, one does not reside in the psychometric catalog. Instead, it appears that a more suitable approach is to customize a set of workload measures based on the task. The novel approach of assessing the sensitivity and comprehensive ability of conjointly utilizing subjective, performance, and physiological workload measures for theoretically different tasks within the same domain contributes to the theory by laying the foundation for improving methodology for researching workload. The applicable contribution of this project is a stepping-stone towards developing complex profiles of workload for use in closed-loop systems, such as human-robot team interaction. Identifying the best combination of workload measures enables human factors practitioners, trainers, and task designers to improve methodology and evaluation of system designs, training requirements, and personnel selection.
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Date Issued
2013
Identifier
CFE0005119, ucf:50675
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005119