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Title: Security of Autonomous Systems under Physical Attacks: With application to Self-Driving Cars.
Creator: Dutta, Raj, Jin, Yier, Sundaram, Kalpathy, DeMara, Ronald, Zhang, Shaojie, Zhang, Teng, University of Central Florida
Abstract / Description: The drive to achieve trustworthy autonomous cyber-physical systems (CPS), which can attain goals independently in the presence of significant uncertainties and for long periods of time without any human intervention, has always been enticing. Significant progress has been made in the avenues of both software and hardware for fulfilling these objectives. However, technological challenges still exist and particularly in terms of decision making under uncertainty. In an autonomous system,...
Show moreThe drive to achieve trustworthy autonomous cyber-physical systems (CPS), which can attain goals independently in the presence of significant uncertainties and for long periods of time without any human intervention, has always been enticing. Significant progress has been made in the avenues of both software and hardware for fulfilling these objectives. However, technological challenges still exist and particularly in terms of decision making under uncertainty. In an autonomous system, uncertainties can arise from the operating environment, adversarial attacks, and from within the system. As a result of these concerns, human-beings lack trust in these systems and hesitate to use them for day-to-day use.In this dissertation, we develop algorithms to enhance trust by mitigating physical attacks targeting the integrity and security of sensing units of autonomous CPS. The sensors of these systems are responsible for gathering data of the physical processes. Lack of measures for securing their information can enable malicious attackers to cause life-threatening situations. This serves as a motivation for developing attack resilient solutions.Among various security solutions, attention has been recently paid toward developing system-level countermeasures for CPS whose sensor measurements are corrupted by an attacker. Our methods are along this direction as we develop an active and multiple passive algorithm to detect the attack and minimize its effect on the internal state estimates of the system. In the active approach, we leverage a challenge authentication technique for detection of two types of attacks: The Denial of Service (DoS) and the delay injection on active sensors of the systems. Furthermore, we develop a recursive least square estimator for recovery of system from attacks. The majority of the dissertation focuses on designing passive approaches for sensor attacks. In the first method, we focus on a linear stochastic system with multiple sensors, where measurements are fused in a central unit to estimate the state of the CPS. By leveraging Bayesian interpretation of the Kalman filter and combining it with the Chi-Squared detector, we recursively estimate states within an error bound and detect the DoS and False Data Injection attacks. We also analyze the asymptotic performance of the estimator and provide conditions for resilience of the state estimate.Next, we propose a novel distributed estimator based on l1 norm optimization, which could recursively estimate states within an error bound without restricting the number of agents of the distributed system that can be compromised. We also extend this estimator to a vehicle platoon scenario which is subjected to sparse attacks. Furthermore, we analyze the resiliency and asymptotic properties of both the estimators. Finally, at the end of the dissertation, we make an initial effort to formally verify the control system of the autonomous CPS using the statistical model checking method. It is done to ensure that a real-time and resource constrained system such as a self-driving car, with controllers and security solutions, adheres to strict timing constrains.
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Date Issued: 2018
Identifier: CFE0007174, ucf:52253
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007174

Title: Context-Centric Affect Recognition From Paralinguistic Features of Speech.
Creator: Marpaung, Andreas, Gonzalez, Avelino, DeMara, Ronald, Sukthankar, Gita, Wu, Annie, Lisetti, Christine, University of Central Florida
Abstract / Description: As the field of affect recognition has progressed, many researchers have shifted from having unimodal approaches to multimodal ones. In particular, the trends in paralinguistic speech affect recognition domain have been to integrate other modalities such as facial expression, body posture, gait, and linguistic speech. Our work focuses on integrating contextual knowledge into paralinguistic speech affect recognition. We hypothesize that a framework to recognize affect through paralinguistic...
Show moreAs the field of affect recognition has progressed, many researchers have shifted from having unimodal approaches to multimodal ones. In particular, the trends in paralinguistic speech affect recognition domain have been to integrate other modalities such as facial expression, body posture, gait, and linguistic speech. Our work focuses on integrating contextual knowledge into paralinguistic speech affect recognition. We hypothesize that a framework to recognize affect through paralinguistic features of speech can improve its performance by integrating relevant contextual knowledge. This dissertation describes our research to integrate contextual knowledge into the paralinguistic affect recognition process from acoustic features of speech. We conceived, built, and tested a two-phased system called the Context-Based Paralinguistic Affect Recognition System (CxBPARS). The first phase of this system is context-free and uses the AdaBoost classifier that applies data on the acoustic pitch, jitter, shimmer, Harmonics-to-Noise Ratio (HNR), and the Noise-to-Harmonics Ratio (NHR) to make an initial judgment about the emotion most likely exhibited by the human elicitor. The second phase then adds context modeling to improve upon the context-free classifications from phase I. CxBPARS was inspired by a human subject study performed as part of this work where test subjects were asked to classify an elicitor's emotion strictly from paralinguistic sounds, and then subsequently provided with contextual information to improve their selections. CxBPARS was rigorously tested and found to, at the worst case, improve the success rate from the state-of-the-art's 42% to 53%.
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Date Issued: 2019
Identifier: CFE0007836, ucf:52831
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007836

Title: Monitoring and Modeling to Estimate Hydrogen Sulfide Emissions and Dispersion from Florida Construction and Demolition Landfills to Construct Odor Buffering Distances.
Creator: Bolyard, Steven, Cooper, Charles, Mackie, Kevin, Randall, Andrew, Zhang, Husen, University of Central Florida
Abstract / Description: Emissions of hydrogen sulfide (H2S) from construction and demolition (C & D) landfills can result in odors that are a significant nuisance to nearby neighborhoods and businesses. As Florida's population continues to grow and create development pressures, housing is built closer to existing landfills. Additionally, new landfills will be created in the future. This research project was undertaken to develop a detailed modeling methodology for use by counties and other landfill owners to provide...
Show moreEmissions of hydrogen sulfide (H2S) from construction and demolition (C & D) landfills can result in odors that are a significant nuisance to nearby neighborhoods and businesses. As Florida's population continues to grow and create development pressures, housing is built closer to existing landfills. Additionally, new landfills will be created in the future. This research project was undertaken to develop a detailed modeling methodology for use by counties and other landfill owners to provide them with an objective and scientifically defensible means to establish odor buffer zones around C & D landfills. A technique for estimating methane (and odorous gas) emissions from municipal solid waste (MSW) landfills was recently developed by researchers at the University of Central Florida. This technique was based on measuring hundreds of ambient methane concentrations near the surface of the landfill, and combining that data with matrix inversion mathematics to back-solve the dispersion equations. The technique was fully documented in two peer-reviewed journal articles. This project extends that methodology. In this work the author measured ambient H2S concentrations at various locations in a C & D landfill, and applied those same matrix inversion techniques to determine the H2S emission rates from the landfill. The emission rates were then input into the AERMOD dispersion model to determine H2S odor buffer distances around the landfill.Three sampling trips to one C & D landfill were undertaken, data were taken, and the modeling techniques were applied. One problem encountered was that H2S emissions from C & D landfills are typically about 1000 times smaller than methane emissions (from MSW landfills). Thus, H2S ambient concentrations often are near the detection limits of the instruments, and the data may not be as reliable. However, this approach could be used for any particular C & D landfill if the appropriate amount of data were available to characterize its emissions with some certainty. The graphical tool developed in this work shows isopleths of (")H2S(") concentrations at various distances, and color codes the isopleths into a (")green-yellow-red(") scheme (analogous to a traffic signal) that depicts zones where private landowners likely will not detect odors, where they may experience some odors, or where they likely will experience odors. The (")likelihood(") can be quantified by selecting the Nth highest hourly concentrations in one year to form the plot. In this study, N was conservatively selected as 8. Requiring that concentrations be at or below the 8th highest concentration in a year corresponds to a 99.9% probability of not exceeding that concentration at that distance in any future year. The graphical tool can be applied to any C & D landfill but each landfill is different. So this technique depends on having a fairly good estimate of the rate of emissions of H2S from the landfill in question, and at least one year's worth of hourly meteorological data (wind speed, direction, and stability class) that is representative of the landfill location. The meteorological data can be obtained with relative ease for most locations in Florida; however, the emission data must be obtained from on-site measurements for any given landfill.
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Date Issued: 2012
Identifier: CFE0004272, ucf:52879
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004272

Title: The influence of an annual meeting on the sense of community of association members, their satisfaction, and future intentions.
Creator: Hahm, Jee Yeon, Breiter, Deborah, Wang, Youcheng, Fjelstul, Jill, Boote, David, Severt, Kimberly, University of Central Florida
Abstract / Description: Over the past decade, many studies have provided some understanding on what influences association members' decision to attend a meeting; however, more systematic and theoretical research is necessary. The decision making process of attendees is a complicated human behavior practice. The major contribution of this study is adopting the sense of community (SOC) model from psychology to gain a better understanding of the attendee behavior. By doing so, this study will add a theoretical...
Show moreOver the past decade, many studies have provided some understanding on what influences association members' decision to attend a meeting; however, more systematic and theoretical research is necessary. The decision making process of attendees is a complicated human behavior practice. The major contribution of this study is adopting the sense of community (SOC) model from psychology to gain a better understanding of the attendee behavior. By doing so, this study will add a theoretical foundation to the existing research in the meeting industry. Also, this study will contribute to the SOC research in psychology by applying the concept to a different setting. This study investigates whether annual conferences build a SOC among association members. First, the SOC of association members at the conference will be analyzed. Second, the influence of SOC on members' satisfaction with the conference will be studied. Lastly, the direct and indirect relationship between SOC and future intentions (i.e., return to next meeting, membership renewal, and membership recommendation) will be examined. Data was collected through an intercept survey approach at three annual conferences of national/international associations. The questionnaire consisted of four sections: sense of community, satisfaction with the conference, future intentions, and member profile. Confirmatory factor analysis was conducted to test the factor structure and structural equation modeling was used to examine the relationships, and Spearman's rank order correlation was used to see the strength of the relationship between respondent characteristics and sense of community. The results showed that sense of community was a strong predictor of future intentions. Implications, limitations, and suggestions for future research are discussed in the final chapter.
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Date Issued: 2012
Identifier: CFE0004543, ucf:49247
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004543

Title: Risk Management in Reservoir Operations in the Context of Undefined Competitive Consumption.
Creator: Salami, Yunus, Nnadi, Fidelia, Wang, Dingbao, Chopra, Manoj, Rowney, Alexander, Divo, Eduardo, University of Central Florida
Abstract / Description: Dams and reservoirs with multiple purposes require effective management to fully realize their purposes and maximize efficiency. For instance, a reservoir intended mainly for the purposes of flood control and hydropower generation may result in a system with primary objectives that conflict with each other. This is because higher hydraulic heads are required to achieve the hydropower generation objective while relatively lower reservoir levels are required to fulfill flood control objectives....
Show moreDams and reservoirs with multiple purposes require effective management to fully realize their purposes and maximize efficiency. For instance, a reservoir intended mainly for the purposes of flood control and hydropower generation may result in a system with primary objectives that conflict with each other. This is because higher hydraulic heads are required to achieve the hydropower generation objective while relatively lower reservoir levels are required to fulfill flood control objectives. Protracted imbalances between these two could increase the susceptibility of the system to risks of water shortage or flood, depending on inflow volumes and operational policy effectiveness. The magnitudes of these risks can become even more pronounced when upstream use of the river is unregulated and uncoordinated so that upstream consumptions and releases are arbitrary. As a result, safe operational practices and risk management alternatives must be structured after an improved understanding of historical and anticipated inflows, actual and speculative upstream uses, and the overall hydrology of catchments upstream of the reservoir. One of such systems with an almost yearly occurrence of floods and shortages due to both natural and anthropogenic factors is the dual reservoir system of Kainji and Jebba in Nigeria. To analyze and manage these risks, a methodology that combines a stochastic and deterministic approach was employed. Using methods outlined by Box and Jenkins (1976), autoregressive integrated moving average (ARIMA) models were developed for forecasting Niger river inflows at Kainji reservoir based on twenty-seven-year-long historical inflow data (1970-1996). These were then validated using seven-year inflow records (1997-2003). The model with the best correlation was a seasonal multiplicative ARIMA (2,1,1)x(2,1,2)12 model. Supplementary validation of this model was done with discharge rating curves developed for the inlet of the reservoir using in situ inflows and satellite altimetry data. By comparing net inflow volumes with storage deficit, flood and shortage risk factors at the reservoir were determined based on (a) actual inflows, (b) forecasted inflows (up to 2015), and (c) simulated scenarios depicting undefined competitive upstream consumption. Calculated high-risk years matched actual flood years again suggesting the reliability of the model. Monte Carlo simulations were then used to prescribe safe outflows and storage allocations in order to reduce futuristic risk factors. The theoretical safety levels achieved indicated risk factors below threshold values and showed that this methodology is a powerful tool for estimating and managing flood and shortage risks in reservoirs with undefined competitive upstream consumption.
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Date Issued: 2012
Identifier: CFE0004593, ucf:49193
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004593

Title: CLASS-E CASCODE POWER AMPLIFIER ANALYSIS AND DESIGN FOR LONG TERM RELIABILITY.
Creator: Kutty, Karan, Yuan, Jiann-Shiun, University of Central Florida
Abstract / Description: This study investigated the Class-E power amplifier operating at 5.2 GHz. Since the operation of this amplifier applies a lot of stress on the switching transistor, a cascode topology was applied in order to reduce the drain-source voltage stress. Such an amplifier was designed and optimized in order to improve stability, power added efficiency, and matching. A layout for the said design was then created to be fabrication-ready using the TSMC 0.18 um technology. Post-layout simulations were...
Show moreThis study investigated the Class-E power amplifier operating at 5.2 GHz. Since the operation of this amplifier applies a lot of stress on the switching transistor, a cascode topology was applied in order to reduce the drain-source voltage stress. Such an amplifier was designed and optimized in order to improve stability, power added efficiency, and matching. A layout for the said design was then created to be fabrication-ready using the TSMC 0.18 um technology. Post-layout simulations were performed in order to realize a more realistic circuit performance with the layout design in mind. Long-term stress effects, such as oxide breakdown, on the key transistors were modeled and simulated in order to achieve an understanding of how leakage currents affect the overall circuit performance. Simulated results were compared and contrasted against theoretical understanding using derived equations. Recommendations for future advancements were made for modification and optimization of the circuit by the application of other stress reduction strategies, variation in the class-E topology, and improvement of the driver stage.
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Date Issued: 2010
Identifier: CFE0003360, ucf:48477
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003360

Title: WEB-BASED TIDAL TOOLBOX OF ASTRONOMIC TIDAL DATA FOR THE ATLANTIC INTRACOASTAL WATERWAY, ESTURARIES AND CONTINENTAL SHELF OF THE SOUTH ATLANTIC BIGHT.
Creator: Ruiz, Alfredo, Hagen, Scott, University of Central Florida
Abstract / Description: A high-resolution astronomic tidal model has been developed that includes detailed inshore regions of the Atlantic Intracoastal Waterway and associated estuaries along the South Atlantic Bight. The unique nature of the model's development ensures that the tidal hydrodynamic interaction between the shelf and estuaries is fully described. Harmonic analysis of the model output results in a database of tidal information that extends from a semi-circular arc (radius ~750 km) enclosing the South...
Show moreA high-resolution astronomic tidal model has been developed that includes detailed inshore regions of the Atlantic Intracoastal Waterway and associated estuaries along the South Atlantic Bight. The unique nature of the model's development ensures that the tidal hydrodynamic interaction between the shelf and estuaries is fully described. Harmonic analysis of the model output results in a database of tidal information that extends from a semi-circular arc (radius ~750 km) enclosing the South Atlantic Bight from the North Carolina coast to the Florida Keys, onto the continental shelf and into the full estuarine system. The need for tidal boundary conditions (elevation and velocity) for driving inland waterway models has motivated the development of a software application to extract results from the tidal database which is the basis of this thesis. In this tidal toolbox, the astronomic tidal constituents can be resynthesized for any open water point in the domain over any interval of time in the past, present, or future. The application extracts model results interpolated to a user's exact geographical points of interest, desired time interval, and tidal constituents. Comparison plots of the model results versus historical data are published on the website at 89 tidal gauging stations. All of the aforementioned features work within a zoom-able geospatial interface for enhanced user interaction. In order to make tidal elevation and velocity data available, a web service serves the data to users over the internet. The tidal database of 497,847 nodes and 927,165 elements has been preprocessed and indexed to enable timely access from a typical modern web server. The preprocessing and web services required are detailed in this thesis, as well as the reproducibility of the Tidal Toolbox for new domains.
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Date Issued: 2011
Identifier: CFE0003579, ucf:48910
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003579

Title: Influence of Topographic Elevation Error On Modeled Storm Surge.
Creator: Bilskie, Matthew, Hagen, Scott, Wang, Dingbao, Chopra, Manoj, University of Central Florida
Abstract / Description: The following presents a method for determining topographic elevation error for overland unstructured finite element meshes derived from bare earth LiDAR for use in a shallow water equations model. This thesis investigates the development of an optimal interpolation method to produce minimal error for a given element size. In hydrodynamic studies, it is vital to represent the floodplain as accurately as possible since terrain is a critical factor that influences water flow. An essential step...
Show moreThe following presents a method for determining topographic elevation error for overland unstructured finite element meshes derived from bare earth LiDAR for use in a shallow water equations model. This thesis investigates the development of an optimal interpolation method to produce minimal error for a given element size. In hydrodynamic studies, it is vital to represent the floodplain as accurately as possible since terrain is a critical factor that influences water flow. An essential step in the development of a coastal inundation model is processing and resampling dense bare earth LiDAR to a DEM and ultimately to the mesh nodes; however, it is crucial that the correct DEM grid size and interpolation method be employed for an accurate representation of the terrain. The following research serves two purposes: 1) to assess the resolution and interpolation scheme of bare earth LiDAR data points in terms of its ability to describe the bare earth topography and its subsequent performance during relevant tide and storm surge simulations.
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Date Issued: 2012
Identifier: CFE0004520, ucf:49265
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004520

Title: Exploration of the Impact of Affective Variables on Human Performance in a Live Simulation.
Creator: Westerlund, Ken, Kincaid, John, Sims, Valerie, Chin, Matthew, VanderVeen, Cornelius, University of Central Florida
Abstract / Description: Live simulations play an important role in allowing users to practice and develop skills they learn in training. Although live simulations are playing an increasingly important role in training, ways to improve them are not well understood or documented. In order to improve the efficacy of live simulation and maximize results from funds spent on training; this research examines the relationship between the affective variables of the participants and their performance in the live simulation....
Show moreLive simulations play an important role in allowing users to practice and develop skills they learn in training. Although live simulations are playing an increasingly important role in training, ways to improve them are not well understood or documented. In order to improve the efficacy of live simulation and maximize results from funds spent on training; this research examines the relationship between the affective variables of the participants and their performance in the live simulation. Prior to participating in the instructor development live simulation used in this study two training preference scales were administered to a group of trainees. These scales measured the trainees' locus of control and immersion tendencies. During the live simulation the trainees' performance was evaluated by a panel of expert observers. The trainees also self-reported their performance through the use of a self-rating instrument. Analysis of the data revealed significant positive correlations between the trainees' internal locus of control and their performance in the simulation, both self-reported (p=0.026) and as reported by the expert observers (p=0.033). The correlation between immersion tendency scores and performance in the live simulation were mixed; while not always statistically significant they did reveal some slight positive correlation. This research did provide a number of lessons learned and implications for instructional and simulation developers wishing to employ live simulation in a training environment. These include performance of sub-populations within the greater population of subjects, consideration of roles assigned to participants, and the need to increase presence within the live simulation. Application of these lessons learned can reduce training costs and/or improve the effectiveness of live simulation in a training environment, this in turn can be of significant benefit to instructional and simulation designers. Additionally, understanding these relationships can lead to better assignments of roles or activities within live simulation and improve the transfer of experience from live simulation training to on the job performance. However, additional research needs to be conducted in order to make more conclusive statements regarding the most appropriate affective variable that would allow for predicting transfer of the simulated experience to the 'real' world, the individuals who would benefit most from live simulation, and to develop additional prescriptive methods for improving live simulation utilized in training environments.
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Date Issued: 2013
Identifier: CFE0004958, ucf:49578
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004958

Title: A System Dynamics Model for Manpower and Technology Implementation Trade-off and Cost Estimation.
Creator: Jiang, Hong, Karwowski, Waldemar, Kincaid, John, Reinerman, Lauren, Ahram, Tareq, University of Central Florida
Abstract / Description: The U.S. Navy has been confronted with budget cuts and constraints during recent years. This reduction in budget compels the U.S. Navy to limit the number of manpower and personnel to control costs. Reducing the total ownership cost (TOC) has become a major topic of interest for the Navy as plans are made for current and future fleets. According to the U.S. Government Accountability Office (GAO, 2003), manpower is the most influential component of determining the life cycle cost of a ship....
Show moreThe U.S. Navy has been confronted with budget cuts and constraints during recent years. This reduction in budget compels the U.S. Navy to limit the number of manpower and personnel to control costs. Reducing the total ownership cost (TOC) has become a major topic of interest for the Navy as plans are made for current and future fleets. According to the U.S. Government Accountability Office (GAO, 2003), manpower is the most influential component of determining the life cycle cost of a ship. The vast majority of the TOC is comprised of operating and support (O(&)S) costs which account for approximately 65 percent of the TOC. Manpower and personnel costs account for approximately 50 percent of O(&)S costs. This research focused on tradeoff analysis and cost estimation between manpower and new technology implementation. Utilizing concepts from System Dynamics Modeling (SDM), System Dynamics Causal Loop diagrams (CLD) were built to identify major factors when implementing new technology, and then stocks and flows diagrams were developed to estimate manpower cost associated with new technology implementation. The SDM base model reflected an 18 months period for technology implementation, and then compared different technology implementation for different scenarios. This model had been tested by the public data from Department of the Navy (DoN) Budget estimates.The objective of this research was to develop a SDM to estimate manpower cost and technology tradeoff analysis associated with different technology implementations. This research will assist Navy decision makers and program managers when objectively considering the impacts of technology selection on manpower and associated TOC, and will provide managers with a better understanding of hidden costs associated with new technology adoption. Recommendations were made for future study in manpower cost estimation of ship systems. In future studies, one particular type of data should be located to test the model for a specific manpower configuration.
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Date Issued: 2013
Identifier: CFE0004869, ucf:49662
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004869

Title: EVALUATING AN ONLINE PERSONALIZED FAMILY-BASED INTERVENTION TO PROMOTE HEALTHY LIFESTYLE CHANGES.
Creator: Hayes, Sharon, Tantleff-Dunn, Stacey, University of Central Florida
Abstract / Description: The current study evaluated the initial feasibility, efficacy, and acceptability of a motivationally-tailored family-based intervention designed to promote the adoption of healthy lifestyle behaviors associated with physical activity and nutrition. Parents (N=132) of children 6 to 11 years old were randomly assigned to the intervention or control condition, and they completed a series of online questionnaires. Intervention participants (n=61) received a single motivationally-tailored feedback...
Show moreThe current study evaluated the initial feasibility, efficacy, and acceptability of a motivationally-tailored family-based intervention designed to promote the adoption of healthy lifestyle behaviors associated with physical activity and nutrition. Parents (N=132) of children 6 to 11 years old were randomly assigned to the intervention or control condition, and they completed a series of online questionnaires. Intervention participants (n=61) received a single motivationally-tailored feedback report via e-mail. Control participants (n=71) completed measures and immediately received information about a free online resource that provides information about healthy lifestyle behaviors (www.mypyramid.gov). Feasibility data indicate that an online feedback program has high dissemination potential (parents from 31 states participated). However, the current methodology is not sufficient in reaching families who are at greatest risk for developing chronic health conditions associated with obesity or low activity level. In general, the intervention was acceptable to parents. Outcome data revealed that the intervention and control groups did not differ significantly on most variables at one month follow-up. Exploratory analyses provided additional evidence for the importance of including parents and targeting parent-child interactions in the context of pediatric nutrition and physical activity interventions. Limitations and future directions are discussed.
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Date Issued: 2010
Identifier: CFE0003359, ucf:48438
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003359

Title: FACTORS INFLUENCING EFFECTIVENESS OF INTERORGANIZATIONAL NETWORKS AMONG CRISIS MANAGEMENT ORGANIZATIONS: A COMPARATIVE PERSPECTIVE.
Creator: Sahin, Bahadir, Wan, Thomas, University of Central Florida
Abstract / Description: Crisis management has become one of the most important public policy areas in recent decades with greater numbers of manmade and natural disasters. History showed that well-implemented crisis management policies can save lives and reduce costs in a disaster. Literature offered various suggestions for more effective crisis management policies with different techniques utilizing different theoretical frameworks. Informal relationships among crisis management employees were suggested to have a...
Show moreCrisis management has become one of the most important public policy areas in recent decades with greater numbers of manmade and natural disasters. History showed that well-implemented crisis management policies can save lives and reduce costs in a disaster. Literature offered various suggestions for more effective crisis management policies with different techniques utilizing different theoretical frameworks. Informal relationships among crisis management employees were suggested to have a positive impact on crisis management effectiveness. Yet it was not demonstrated with advanced statistical tools if there is such a relationship. This study considers crisis management effort as a network effort and employs complex adaptive systems theory in order to understand factors influencing effectiveness of crisis management networks. Complex adaptive systems theory presents that more open communication lines in a given network or an organization would increase effectiveness of it since inner processes of the network or organization would obtain more information from the chaotic environment. Quality of informal relationships (casual relationships, social capital etc.) was hypothesized as a tool to open more communication lines within an agency which would eventually increase effectiveness of the network constructed by the organization. Based on the theoretical framework, adaptiveness capacity of the agencies was also tested in order to understand a correlation between adaptation and effectiveness of crisis management networks. Multiple case-study method was employed to identify incidents that can represent crisis management in full perspective. Terrorist attacks carried upon by the same terrorist network hit New York in 2001, Istanbul in 2003, Madrid in 2004, and London in 2005 were selected. First response phase of crisis management and policy changes after and before the attacks were discussed. Public administration processes and other social-economical conditions of countries were examined in terms of crisis management structure. Names of key agencies of selected crisis management systems were suggested by a social network analysis tool-UCINET. Six key agencies per incident were targeted for surveys. Surveys included a nine-item-quality of informal relationships, four-item-adaptiveness capability, and ten-item-perceived effectiveness of crisis management networks-scales. Respondents were asked to fill in online surveys where they could refer to their colleagues in the same incidents. 230 respondents were aimed and 246 survey responses were obtained as a result. Surveys formed a structural equation model representing 23 observed factors and 2 latent constructs. Confirmatory factor analysis was utilized to validate hypothesis-driven conceptual models. Quality of informal relationships was found to have a significant positive impact on perceived crisis management network effectiveness (Standardized regression coefficient = .39). Two of the adaptiveness variables, openness to change and intra-organizational training were also positively correlated with the dependent variable of the study (Standardized regression coefficient = .40 and .26 respectively). Turkish and American groups' differences suggested a social-economical difference in societies. Majority of the respondents were some type of managers which made it possible to generalize the results for all phases of crisis management. Discussions suggested improved informal relationships among crisis management employees to provide a better crisis management during an extreme event. Collaborative social events were offered to improve crisis management effectiveness. An agency's openness to change proposed that a crisis management organization should be flexible in rules and structureto gain more efficacy. The other adaptiveness variable, intra-organizational training efforts were proposed to have certain influence on effectiveness of crisis management network. Factors built latent construct of perceived crisis management effectiveness were also found out to be important on crisis management, which of some are ability to carry out generic crisis management functions, mobilize personnel and resources efficiently, process information adequately, blend emergent and established entities, provide appropriate reports for news media etc. Study contributed to the complex adaptive system theory since the fundamentals of the theory were tested with an advanced quantitative method. Non-linear relationships within a system were tested in order to reveal a correlation as the theory suggested, where the results were convincingly positive. Crisis management networks' effectiveness was demonstrated to be validated by a ten-item-scale successfully. Future research might utilize more disaster cases both natural and manmade, search for impact of different communication tools within a system, and look at the relationships among members of crisis management networks instead looking within an organization.
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Date Issued: 2009
Identifier: CFE0002709, ucf:48173
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002709

Title: SOURCE REPRESENTATION AND FRAMING IN CHILDHOOD IMMUNIZATION COMMUNICATION.
Creator: Raneri, April, Matusitz, Jonathan, University of Central Florida
Abstract / Description: Research has indicated a strong interest in knowing who is being represented and how information is being represented in the communication about childhood immunization. This study uses a two-part analysis to look at source representation and framing in childhood immunization communication. A quantitative analysis of articles from the New York Times and USA Today were examined for their source representation, their use of fear appeals, through the Extended Parallel Processing Model (EPPM), and...
Show moreResearch has indicated a strong interest in knowing who is being represented and how information is being represented in the communication about childhood immunization. This study uses a two-part analysis to look at source representation and framing in childhood immunization communication. A quantitative analysis of articles from the New York Times and USA Today were examined for their source representation, their use of fear appeals, through the Extended Parallel Processing Model (EPPM), and the use of frames, through the application of Prospect Theory. A qualitative semiotic analysis was conducted on 36 images that appeared on www.yahoo.com and www.google.com to find common themes for who is being represented and how information is being portrayed through the images. Results found a high prevalence of representation from the Center for Disease Control and Prevention, other governmental agencies and views from health/medical professionals in both the articles and images.
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Date Issued: 2010
Identifier: CFE0003016, ucf:48343
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003016

Title: EXPLOITING OPPONENT MODELING FOR LEARNING IN MULTI-AGENT ADVERSARIAL GAMES.
Creator: Laviers, Kennard, Sukthankar, Gita, University of Central Florida
Abstract / Description: An issue with learning effective policies in multi-agent adversarial games is that the size of the search space can be prohibitively large when the actions of both teammates and opponents are considered simultaneously. Opponent modeling, predicting an opponent's actions in advance of execution, is one approach for selecting actions in adversarial settings, but it is often performed in an ad hoc way. In this dissertation, we introduce several methods for using opponent modeling, in the form of...
Show moreAn issue with learning effective policies in multi-agent adversarial games is that the size of the search space can be prohibitively large when the actions of both teammates and opponents are considered simultaneously. Opponent modeling, predicting an opponent's actions in advance of execution, is one approach for selecting actions in adversarial settings, but it is often performed in an ad hoc way. In this dissertation, we introduce several methods for using opponent modeling, in the form of predictions about the players' physical movements, to learn team policies. To explore the problem of decision-making in multi-agent adversarial scenarios, we use our approach for both offline play generation and real-time team response in the Rush 2008 American football simulator. Simultaneously predicting the movement trajectories, future reward, and play strategies of multiple players in real-time is a daunting task but we illustrate how it is possible to divide and conquer this problem with an assortment of data-driven models. By leveraging spatio-temporal traces of player movements, we learn discriminative models of defensive play for opponent modeling. With the reward information from previous play matchups, we use a modified version of UCT (Upper Conference Bounds applied to Trees) to create new offensive plays and to learn play repairs to counter predicted opponent actions. In team games, players must coordinate effectively to accomplish tasks while foiling their opponents either in a preplanned or emergent manner. An effective team policy must generate the necessary coordination, yet considering all possibilities for creating coordinating subgroups is computationally infeasible. Automatically identifying and preserving the coordination between key subgroups of teammates can make search more productive by pruning policies that disrupt these relationships. We demonstrate that combining opponent modeling with automatic subgroup identification can be used to create team policies with a higher average yardage than either the baseline game or domain-specific heuristics.
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Date Issued: 2011
Identifier: CFE0003914, ucf:48720
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003914

Title: Describing Images by Semantic Modeling using Attributes and Tags.
Creator: Mahmoudkalayeh, Mahdi, Shah, Mubarak, Sukthankar, Gita, Rahnavard, Nazanin, Zhang, Teng, University of Central Florida
Abstract / Description: This dissertation addresses the problem of describing images using visual attributes and textual tags, a fundamental task that narrows down the semantic gap between the visual reasoning of humans and machines. Automatic image annotation assigns relevant textual tags to the images. In this dissertation, we propose a query-specific formulation based on Weighted Multi-view Non-negative Matrix Factorization to perform automatic image annotation. Our proposed technique seamlessly adapt to the...
Show moreThis dissertation addresses the problem of describing images using visual attributes and textual tags, a fundamental task that narrows down the semantic gap between the visual reasoning of humans and machines. Automatic image annotation assigns relevant textual tags to the images. In this dissertation, we propose a query-specific formulation based on Weighted Multi-view Non-negative Matrix Factorization to perform automatic image annotation. Our proposed technique seamlessly adapt to the changes in training data, naturally solves the problem of feature fusion and handles the challenge of the rare tags. Unlike tags, attributes are category-agnostic, hence their combination models an exponential number of semantic labels. Motivated by the fact that most attributes describe local properties, we propose exploiting localization cues, through semantic parsing of human face and body to improve person-related attribute prediction. We also demonstrate that image-level attribute labels can be effectively used as weak supervision for the task of semantic segmentation. Next, we analyze the Selfie images by utilizing tags and attributes. We collect the first large-scale Selfie dataset and annotate it with different attributes covering characteristics such as gender, age, race, facial gestures, and hairstyle. We then study the popularity and sentiments of the selfies given an estimated appearance of various semantic concepts. In brief, we automatically infer what makes a good selfie. Despite its extensive usage, the deep learning literature falls short in understanding the characteristics and behavior of the Batch Normalization. We conclude this dissertation by providing a fresh view, in light of information geometry and Fisher kernels to why the batch normalization works. We propose Mixture Normalization that disentangles modes of variation in the underlying distribution of the layer outputs and confirm that it effectively accelerates training of different batch-normalized architectures including Inception-V3, Densely Connected Networks, and Deep Convolutional Generative Adversarial Networks while achieving better generalization error.
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Date Issued: 2019
Identifier: CFE0007493, ucf:52640
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007493

Title: Genetically-programmed suicide of adrenergic cells in the mouse leads to severe left ventricular dysfunction, impaired weight gain, and symptoms of neurological dysfunction.
Creator: Owji, Aaron, Ebert, Steven, King, Stephen, Sugaya, Kiminobu, University of Central Florida
Abstract / Description: Phenylethanolamine-N-methyltransferase (Pnmt) catalyzes the conversion of noradrenaline to adrenaline and is the last enzyme in the catecholamine biosynthetic pathway. Pnmt serves as a marker for adrenergic cells, and lineage-tracing experiments have identified the embryonic heart and hindbrain region as the first sites of Pnmt expression in the mouse. Pnmt expression in the heart occurs before the adrenal glands have formed and prior to sympathetic innervation, suggesting that the heart is...
Show morePhenylethanolamine-N-methyltransferase (Pnmt) catalyzes the conversion of noradrenaline to adrenaline and is the last enzyme in the catecholamine biosynthetic pathway. Pnmt serves as a marker for adrenergic cells, and lineage-tracing experiments have identified the embryonic heart and hindbrain region as the first sites of Pnmt expression in the mouse. Pnmt expression in the heart occurs before the adrenal glands have formed and prior to sympathetic innervation, suggesting that the heart is the first site of catecholamine production in the mouse. The function of these Pnmt+ cells in heart development remains unclear. In the present study, we test the hypothesis that (i) a genetic ablation technique utilizing a suicide reporter gene selectively destroys Pnmt cells in the mouse, and (ii) Pnmt cells are required for normal cardiovascular and neurological function.To genetically ablate adrenergic cells, we mated Pnmt-Cre mice, in which Cre-recombinase is under the transcriptional regulation of the Pnmt promoter, and a Cre -activated diphtheria toxin A (DTA) mouse strain (ROSA26-eGFP-DTA), thereby causing activation of the toxic allele (DTA) in Pnmt-expressing (adrenergic) cells resulting in selective (")suicide(") of these cells in approximately half of the offspring. The other half serve as controls because they do not have the ROSA26-eGFP-DTA construct. In the Pnmt+/Cre; R26+/DTA offspring, we achieve a dramatic reduction in Pnmt transcript and Pnmt immunoreactive area in the adrenal glands. Furthermore, we show that loss of Pnmt cells results in severe left ventricular dysfunction that progressively worsens with age. These mice exhibit severely reduced cardiac output and ejection fraction due to decreased LV contractility and bradycardia at rest. Surprisingly, these mice appear to have a normal stress response, as heart rate and ejection fraction increased to a similarextent compared to controls. In addition to baseline cardiac dysfunction, these mice fail to gain body weight in a normal manner and display gross neurological dysfunction, including muscular weakness, abnormal gaiting, and altered tail suspension reflex, an indicator of neurological function.This work demonstrates that selective Pnmt cell destruction leads to severe left ventricular dysfunction, lack of weight gain, and neurological dysfunction. This novel mouse is expected to shed insight into the role of Pnmt cells in the heart, and suggests a role for Pnmt cells in neurological regulation of feeding behavior, metabolism, and motor control.
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Date Issued: 2015
Identifier: CFE0006048, ucf:50984
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006048

Title: Inverse-Consistent Determination of Young's Modulus of Human Lung.
Creator: Seyfi Noferest, Behnaz, Ilegbusi, Olusegun, Santhanam, Anand, Kassab, Alain, Moslehy, Faissal, University of Central Florida
Abstract / Description: Human lung undergoes respiration-induced deformation due to sequential inhalation and exhalation. Accurate determination of lung deformation is crucial for tumor localization and targeted radiotherapy in patients with lung cancer. Numerical modeling of human lung dynamics based on underlying physics and physiology enables simulation and virtual visualization of lung deformation. Dynamical modeling is numerically complicated by the lack of information on lung elastic behavior, structural...
Show moreHuman lung undergoes respiration-induced deformation due to sequential inhalation and exhalation. Accurate determination of lung deformation is crucial for tumor localization and targeted radiotherapy in patients with lung cancer. Numerical modeling of human lung dynamics based on underlying physics and physiology enables simulation and virtual visualization of lung deformation. Dynamical modeling is numerically complicated by the lack of information on lung elastic behavior, structural heterogeneity as well as boundary constrains. This study integrates physics-based modeling and image-based data acquisition to develop the patient-specific biomechanical model and consequently establish the first consistent Young's modulus (YM) of human lung. This dissertation has four major components: (i) develop biomechanical model for computation of the flow and deformation characteristics that can utilize subject-specific, spatially-dependent lung material property; (ii) develop a fusion algorithm to integrate deformation results from a deformable image registration (DIR) and physics-based modeling using the theory of Tikhonov regularization; (iii) utilize fusion algorithm to establish unique and consistent patient specific Young's modulus and; (iv) validate biomechanical model utilizing established patient-specific elastic property with imaging dataThe simulation is performed on three dimensional lung geometry reconstructed from four-dimensional computed tomography (4DCT) dataset of human subjects. The heterogeneous Young's modulus is estimated from a linear elastic deformation model with the same lung geometry and 4D lung DIR. The biomechanical model adequately predicts the spatio-temporal lung deformation, consistent with data obtained from imaging. The accuracy of the numerical solution is enhanced through fusion with the imaging data beyond the classical comparison of the two sets of data. Finally, the fused displacement results are used to establish unique and consistent patient-specific elastic property of the lung.
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Date Issued: 2015
Identifier: CFE0006391, ucf:51512
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006391

Title: Load Estimation, Structural Identification and Human Comfort Assessment of Flexible Structures.
Creator: Celik, Ozan, Catbas, Necati, Yun, Hae-Bum, Makris, Nicos, Kauffman, Jeffrey L., University of Central Florida
Abstract / Description: Stadiums, pedestrian bridges, dance floors, and concert halls are distinct from other civil engineering structures due to several challenges in their design and dynamic behavior. These challenges originate from the flexible inherent nature of these structures coupled with human interactions in the form of loading. The investigations in past literature on this topic clearly state that the design of flexible structures can be improved with better load modeling strategies acquired with reliable...
Show moreStadiums, pedestrian bridges, dance floors, and concert halls are distinct from other civil engineering structures due to several challenges in their design and dynamic behavior. These challenges originate from the flexible inherent nature of these structures coupled with human interactions in the form of loading. The investigations in past literature on this topic clearly state that the design of flexible structures can be improved with better load modeling strategies acquired with reliable load quantification, a deeper understanding of structural response, generation of simple and efficient human-structure interaction models and new measurement and assessment criteria for acceptable vibration levels. In contribution to these possible improvements, this dissertation taps into three specific areas: the load quantification of lively individuals or crowds, the structural identification under non-stationary and narrowband disturbances and the measurement of excessive vibration levels for human comfort. For load quantification, a computer vision based approach capable of tracking both individual and crowd motion is used. For structural identification, a noise-assisted Multivariate Empirical Mode Decomposition (MEMD) algorithm is incorporated into the operational modal analysis. The measurement of excessive vibration levels and the assessment of human comfort are accomplished through computer vision based human and object tracking, which provides a more convenient means for measurement and computation. All the proposed methods are tested in the laboratory environment utilizing a grandstand simulator and in the field on a pedestrian bridge and on a football stadium. Findings and interpretations from the experimental results are presented. The dissertation is concluded by highlighting the critical findings and the possible future work that may be conducted.
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Date Issued: 2017
Identifier: CFE0006863, ucf:51752
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006863

Title: An Investigation of the Help-Seeking Behaviors of Women Student Veterans.
Creator: Armstrong, Tanya, Cox, Dr. Thomas, Whiteman, JoAnn, Hopp, Carolyn, Grauerholz, Liz, University of Central Florida
Abstract / Description: Women with military experience are attending colleges and universities across the United States. It is important to understand how they describe their experiences as students and how their help-seeking behaviors impact their success (DiRamio (&) Jarvis, 2011; Baechtold (&) Da Sawal, 2009). Using Schlossberg's Adult Transition Theory (1981, 1984) as a framework, this qualitative phenomenological study explored the help-seeking behaviors of women student veterans. In addition, the events that...
Show moreWomen with military experience are attending colleges and universities across the United States. It is important to understand how they describe their experiences as students and how their help-seeking behaviors impact their success (DiRamio (&) Jarvis, 2011; Baechtold (&) Da Sawal, 2009). Using Schlossberg's Adult Transition Theory (1981, 1984) as a framework, this qualitative phenomenological study explored the help-seeking behaviors of women student veterans. In addition, the events that caused them to seek help and the resources they utilized are described. The research questions were: (1) Does the prior military experience of women student veterans influence their willingness to seek help? (2) What are the events that cause women student veterans to seek help? And (3) What are the resources that women student veterans utilize? Using Smith, Flowers and Larkin's (2009) Interpretative Phenomenological Analysis (IPA), this two-phase mixed method design employed a sequential descriptive strategy employing a profile questionnaire and individual semi-structured interviews (N=9). The research identified six themes using Schlossberg's framework (1981, 1984). These six themes were: military influence, transitions, times of distress, tailored support, traditional support and support 'from my own'. The findings of this study provide researchers, student personnel professionals, and military educational constituencies with a foundation for policy and programming that account for the help seeking behaviors women student veterans' exhibit as they transition from the military to college.
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Date Issued: 2017
Identifier: CFE0006560, ucf:51313
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006560

Title: A Simulation-Based Task Analysis using Agent-Based, Discrete Event and System Dynamics simulation.
Creator: Angelopoulou, Anastasia, Karwowski, Waldemar, Kincaid, John, Xanthopoulos, Petros, Hancock, Peter, University of Central Florida
Abstract / Description: Recent advances in technology have increased the need for using simulation models to analyze tasks and obtain human performance data. A variety of task analysis approaches and tools have been proposed and developed over the years. Over 100 task analysis methods have been reported in the literature. However, most of the developed methods and tools allow for representation of the static aspects of the tasks performed by expert system-driven human operators, neglecting aspects of the work...
Show moreRecent advances in technology have increased the need for using simulation models to analyze tasks and obtain human performance data. A variety of task analysis approaches and tools have been proposed and developed over the years. Over 100 task analysis methods have been reported in the literature. However, most of the developed methods and tools allow for representation of the static aspects of the tasks performed by expert system-driven human operators, neglecting aspects of the work environment, i.e. physical layout, and dynamic aspects of the task. The use of simulation can help face the new challenges in the field of task analysis as it allows for simulation of the dynamic aspects of the tasks, the humans performing them, and their locations in the environment. Modeling and/or simulation task analysis tools and techniques have been proven to be effective in task analysis, workload, and human reliability assessment. However, most of the existing task analysis simulation models and tools lack features that allow for consideration of errors, workload, level of operator's expertise and skills, among others. In addition, the current task analysis simulation tools require basic training on the tool to allow for modeling the flow of task analysis process and/or error and workload assessment. The modeling process is usually achieved using drag and drop functionality and, in some cases, programming skills.This research focuses on automating the modeling process and simulating individuals (or groups of individuals) performing tasks in a dynamic work environment in any domain. The main objective of this research is to develop a universal tool that allows for modeling and simulation of task analysis models in a short amount of time with limited need for training or knowledge of modeling and simulation theory. A Universal Task Analysis Simulation Modeling (UTASiMo) tool can be used for automatically generating simulation models that analyze the tasks performed by human operators. UTASiMo is a multi-method modeling and simulation tool developed as a combination of agent-based, discrete event, and system dynamics simulation models. A generic multi-method modeling and simulation framework, named 3M(&)S Framework, as well as the Unified Modeling Language have been used for the design of the conceptual model and the implementation of the simulation tool. UTASiMo-generated models are dynamically created during run-time based on user inputs. The simulation results include estimations of operator workload, task completion time, and probability of human errors based on human operator variability and task structure.
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Date Issued: 2015
Identifier: CFE0006252, ucf:51040
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006252

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