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- Title
- THE RELATIONSHIP BETWEEN ADMISSION CREDENTIALS AND THE SUCCESS OF STUDENTS ADMITTED TO A PHYSICS DOCTORAL PROGRAM.
- Creator
-
Wilkerson, Teresa, Tubbs, LeVester, University of Central Florida
- Abstract / Description
-
The researcher developed this study based on the Hardgrave, et al. (1993)statement that for a doctoral student, it was "more than just standardized scores, previous academic performance, and past work experience ultimately affects whether the candidate will be successful in the program" (p. 261). This study examined both the subjective and quantifiable aspects of application materials to a physics doctoral program to explore potential relationships between the credentials presented in the...
Show moreThe researcher developed this study based on the Hardgrave, et al. (1993)statement that for a doctoral student, it was "more than just standardized scores, previous academic performance, and past work experience ultimately affects whether the candidate will be successful in the program" (p. 261). This study examined both the subjective and quantifiable aspects of application materials to a physics doctoral program to explore potential relationships between the credentials presented in the application and the ultimate success of the admitted students. The researcher developed questions with the goals of addressing the problem of attrition in doctoral programs and gaining a better of understanding the information provided in students' application packets. The researcher defined success as either enrolled four years after admission or attainment of the degree. This study examined the records of a population of students admitted to a physics doctoral program from the fall of 1997 to the fall of 2003 to determine their level of success as of August 2006. An exploratory analysis of the data provided answers to each of the research questions as well as an extensive understanding of the students admitted into the program during this time. This study examined both admission credentials and constructs identified by past researchers. An evaluation of the data gathered in this research revealed no relationships between these and student success as previously defined. In 1974, Willingham stated simply, "the best way to improve selection of graduate students will be to develop improved criteria for success" (p. 278). To this end, recommendations emerged regarding the decision-making process and suggestions for future research. This study was not developed to prove or disprove past research findings that predicted success from admissions information; rather, the researcher developed this study to explore each of the credentials that a student presents with his or her application packet, and to tell the story about the nuances of these credentials as they related to student success in a physics doctoral program.
Show less - Date Issued
- 2007
- Identifier
- CFE0001524, ucf:47154
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001524
- Title
- Examining Users' Application Permissions On Android Mobile Devices.
- Creator
-
Safi, Muhammad, Wisniewski, Pamela, Leavens, Gary, Hughes, Charles, University of Central Florida
- Abstract / Description
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Mobile devices have become one of the most important computing platforms. The platform's portability and highly customized nature raises several privacy concerns. Therefore, understanding and predicting user privacy behavior has become very important if one is to design software which respects the privacy concerns of users. Various studies have been carried out to quantify user perceptions and concerns [23,36] and user characteristics which may predict privacy behavior [21,22,25]. Even though...
Show moreMobile devices have become one of the most important computing platforms. The platform's portability and highly customized nature raises several privacy concerns. Therefore, understanding and predicting user privacy behavior has become very important if one is to design software which respects the privacy concerns of users. Various studies have been carried out to quantify user perceptions and concerns [23,36] and user characteristics which may predict privacy behavior [21,22,25]. Even though significant research exists regarding factors which affect user privacy behavior, there is gap in the literature when it comes to correlating these factors to objectively collected data from user devices. We designed an Android application which administered surveys to collect various perceived measures, and to scrape past behavioral data from the phone. Our goal was to discover variables which help in predicting user location sharing decisions by correlating what we collected from surveys with the user's decision to share their location with our study application. We carried out logistic regression analysis with multiple measured variables and found that perceived measures and past behavioral data alone were poor predictors of user location sharing decisions. Instead, we discovered that perceived measures in the context of past behavior helped strengthen prediction models. Asking users to reflect on whether they were comfortable sharing their location with apps that were already installed on their mobile device was a stronger predictor of location sharing behavior than general measures regarding privacy concern or past behavioral data scraped from their phones. This work contributes to the field by correlating existing privacy measures with objective data, and uncovering a new predictor of location sharing decisions.
Show less - Date Issued
- 2018
- Identifier
- CFE0007363, ucf:52085
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007363
- Title
- THE USE OF MOBILE APPLICATIONS IN PREVENTIVE CARE AND HEALTH-RELATED CONDITIONS: A REVIEW OF THE LITERATURE.
- Creator
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Ringer, Naomi, D'Amato-Kubiet, Leslee, University of Central Florida
- Abstract / Description
-
The purpose of this review of literature was to understand the role of mobile device applications in health related conditions and to analyze their effects on health outcomes related to the management of chronic illnesses. Implications for future use of applications in client-centered care and interpretation of the data by health care providers was also explored. Peer-reviewed, English-language research articles published from 2008 to present were included for synthesis. Study results...
Show moreThe purpose of this review of literature was to understand the role of mobile device applications in health related conditions and to analyze their effects on health outcomes related to the management of chronic illnesses. Implications for future use of applications in client-centered care and interpretation of the data by health care providers was also explored. Peer-reviewed, English-language research articles published from 2008 to present were included for synthesis. Study results revealed positive outcomes when health-related mobile applications were used in practice and support clinicians' use of mobile applications as a tool for monitoring symptoms and communicating with individuals. The literature indicated nurses play a significant role in providing feedback, which reinforces self-care strategies and adherence, with the potential for improving outcomes. Additional research is needed to evaluate the long-term effects of applications on patient outcomes, nurses' perspectives, and feasibility of implementation into practice.
Show less - Date Issued
- 2014
- Identifier
- CFH0004660, ucf:45280
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004660
- Title
- A SOFTWARE-BASED KNOWLEDGE MANAGEMENT SYSTEM USING NARRATIVE TEXTS.
- Creator
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McDaniel, Thomas Rudy, Dombrowski, Paul, University of Central Florida
- Abstract / Description
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Technical and professional communicators have in recent research been challenged to make significant contributions to the field of knowledge management, and to learn or create the new technologies allowing them to do so. The purpose of this dissertation is to make such a combined theoretical and applied contribution from the context of the emerging discipline of Texts and Technology. This dissertation explores the field of knowledge management (KM), particularly its relationship to the...
Show moreTechnical and professional communicators have in recent research been challenged to make significant contributions to the field of knowledge management, and to learn or create the new technologies allowing them to do so. The purpose of this dissertation is to make such a combined theoretical and applied contribution from the context of the emerging discipline of Texts and Technology. This dissertation explores the field of knowledge management (KM), particularly its relationship to the related study of artificial intelligence (AI), and then recommends a KM software application based on the principles of narratology and narrative information exchange. The focus of knowledge is shifted from the reductive approach of data and information to a holistic approach of meaning and the way people make sense of complex events as experiences expressed in stories. Such an analysis requires a discussion of the evolution of intelligent systems and narrative theory as well as an examination of existing computerized and non-computerized storytelling systems. After a thorough discussion of these issues, an original software program that is used to collect, analyze, and distribute thematic stories within any hierarchical organization is modeled, exemplified, and explained in detail.
Show less - Date Issued
- 2004
- Identifier
- CFE0000012, ucf:46117
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000012
- Title
- She's Not Fit for the Business World: An Initial Examination of Gender, Age, and Weight.
- Creator
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Pelkey, Miranda, Fritzsche, Barbara, Joseph, Dana, Pace, Victoria, University of Central Florida
- Abstract / Description
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The present study examined archetype theory (Marcus (&) Fritzsche, 2015) that suggests that the intersection of multiple group memberships will create a unique cognitive representation, as it is relates to sex, age, and weight. Following a pilot study to equate photos on attractiveness, perceived competence, professionalism, and intelligence, 183 participants reviewed a fictitious LinkedIn profile in which all information was held constant across participants except the photo. Using a 2 (sex)...
Show moreThe present study examined archetype theory (Marcus (&) Fritzsche, 2015) that suggests that the intersection of multiple group memberships will create a unique cognitive representation, as it is relates to sex, age, and weight. Following a pilot study to equate photos on attractiveness, perceived competence, professionalism, and intelligence, 183 participants reviewed a fictitious LinkedIn profile in which all information was held constant across participants except the photo. Using a 2 (sex) x 2 (age) x 2 (weight) design (manipulated through the photos), participants rated the job applicant on adjectives associated with proposed sex, age, and weight archetypes and on perceptions of job suitability. Results showed that the most young, overweight female received the highest ratings on negative adjectives (i.e., lazy, uncontrolled, self-indulgent) and was rated lower than most conditions on job suitability. Overweight conditions received lower ratings on job suitability than their average-weight counterpart. Weight also impacted the old, female, such that the old, overweight female received lower ratings than her average-weight counterpart on job suitability. In order to help individuals who face disadvantages and unfair treatment in the workplace, the negative effects multiple-group membership has on certain groups must first be acknowledged.
Show less - Date Issued
- 2016
- Identifier
- CFE0006161, ucf:51156
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006161
- Title
- Tiling with Polyominoes, Polycubes, and Rectangles.
- Creator
-
Saxton, Michael, Reid, Michael, Lee, Junho, Han, Deguang, University of Central Florida
- Abstract / Description
-
In this paper we study the hierarchical structure of the 2-d polyominoes. We introduce a new infinite family of polyominoes which we prove tiles a strip. We discuss applications of algebra to tiling. We discuss the algorithmic decidability of tiling the infinite plane Z x Z given a finite set of polyominoes. We will then discuss tiling with rectangles. We will then get some new, and some analogous results concerning the possible hierarchical structure for the 3-d polycubes.
- Date Issued
- 2015
- Identifier
- CFE0005995, ucf:50791
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005995
- Title
- Determinants of continuance intention and word of mouth for hotel branded mobile app users.
- Creator
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Cobos, Liza, Wang, Youcheng, Kaufman, Tammie, Okumus, Fevzi, University of Central Florida
- Abstract / Description
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This study examined the cognitive and affective factors that influence users' post-adoption behavioral intention. Specifically, based on the Expectation Confirmation Model (ECM) (Bhattacherjee, 2001b) the impact of cognitive factors (i.e., perceived usefulness, confirmation of expectations, mobility, personalization and responsiveness) and affective factors (i.e., satisfaction, perceived enjoyment) on hotel branded mobile applications (apps) users' continuance intention and WOM were examined....
Show moreThis study examined the cognitive and affective factors that influence users' post-adoption behavioral intention. Specifically, based on the Expectation Confirmation Model (ECM) (Bhattacherjee, 2001b) the impact of cognitive factors (i.e., perceived usefulness, confirmation of expectations, mobility, personalization and responsiveness) and affective factors (i.e., satisfaction, perceived enjoyment) on hotel branded mobile applications (apps) users' continuance intention and WOM were examined. Hospitality firms invest considerable resources on technology solutions that are aimed at improving the consumer experience. However, for investments to be profitable firms must ensure that technology solutions are continuously used and ensure post-adoptive behaviors such as continuance intention and WOM. Data for the study were collected from 550 hotel branded mobile app users. After data were collected and cleaned, Partial Least-Square Structural Equation Modeling (PLS-SEM) was used to analyze the data. The results of the structural model indicated that continuance intention and WOM were directly influenced by satisfaction and perceived enjoyment; with satisfaction exerting the most influence on continuance intention. Conversely, perceived enjoyment was most influential to WOM. All cognitive factors were found to influence satisfaction and enjoyment, except for responsiveness and perceived usefulness. The results show that contextual factors have a more significant impact than previously established constructs. The results of the study allow hoteliers and hospitality technology consultants to identify the influential factors impacting post-adoptive behaviors. The study extends the literature on post-adoptive behavior and the ECM by including context specific factors (i.e. perceived mobility, personalization and responsiveness). This study contributes to the scare literature in the lodging industry literature examining users' evaluations of mobile apps and post-adoptive behaviors in the hospitality industry. The study adds to the post-adoptive behavior literature by adding WOM as a second outcome to continuance intention. The treatment of contextual factors in this study, allowed to show the impact technology characteristics have on technology post-adoption.
Show less - Date Issued
- 2017
- Identifier
- CFE0006868, ucf:51743
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006868
- Title
- The Impact of Individual Perceptions of the Fairness of Public Affirmative Action Policy Statements on Attitudes toward the Organization.
- Creator
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Zaragoza, Joseph, Wooten, William, Carter, Nathan, Fritzsche, Barbara, University of Central Florida
- Abstract / Description
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The purpose of this research project was to explore differences in perceptions of organizational justice and related attitudes. Through the use of a 3 x 2 experimental design, participants were randomly assigned to groups in which they were exposed to a fictitious organization's mock recruitment document publicizing different types of affirmative action programs and varying levels of information regarding the mechanics of such programs. Results did not demonstrate statistically significant...
Show moreThe purpose of this research project was to explore differences in perceptions of organizational justice and related attitudes. Through the use of a 3 x 2 experimental design, participants were randomly assigned to groups in which they were exposed to a fictitious organization's mock recruitment document publicizing different types of affirmative action programs and varying levels of information regarding the mechanics of such programs. Results did not demonstrate statistically significant differences across groups. Project implications, limitations, and suggestions for future research are discussed.
Show less - Date Issued
- 2012
- Identifier
- CFE0004622, ucf:49938
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004622
- Title
- Autonomous Quadcopter Videographer.
- Creator
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Coaguila Quiquia, Rey, Sukthankar, Gita, Wu, Annie, Hughes, Charles, University of Central Florida
- Abstract / Description
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In recent years, the interest in quadcopters as a robotics platform for autonomous photography has increased. This is due to their small size and mobility, which allow them to reach places that are difficult or even impossible for humans. This thesis focuses on the design of an autonomous quadcopter videographer, i.e. a quadcopter capable of capturing good footage of a specific subject. In order to obtain this footage, the system needs to choose appropriate vantage points and control the...
Show moreIn recent years, the interest in quadcopters as a robotics platform for autonomous photography has increased. This is due to their small size and mobility, which allow them to reach places that are difficult or even impossible for humans. This thesis focuses on the design of an autonomous quadcopter videographer, i.e. a quadcopter capable of capturing good footage of a specific subject. In order to obtain this footage, the system needs to choose appropriate vantage points and control the quadcopter. Skilled human videographers can easily spot good filming locations where the subject and its actions can be seen clearly in the resulting video footage, but translating this knowledge to a robot can be complex. We present an autonomous system implemented on a commercially available quadcopter that achieves this using only the monocular information and an accelerometer. Our system has two vantage point selection strategies: 1) a reactive approach, which moves the robot to a fixed location with respect to the human and 2) the combination of the reactive approach and a POMDP planner that considers the target's movement intentions. We compare the behavior of these two approaches under different target movement scenarios. The results show that the POMDP planner obtains more stable footage with less quadcopter motion.
Show less - Date Issued
- 2015
- Identifier
- CFE0005592, ucf:50246
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005592
- Title
- Managing, Controlling and Improving the Treatment of Produced Water Using the Six Sigma Methodology for the Iraqi Oil Fields.
- Creator
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Al-Shamkhani, Maher T., Elshennawy, Ahmad, Rabelo, Luis, Pazour, Jennifer, Xanthopoulos, Petros, University of Central Florida
- Abstract / Description
-
Produced Water (PW) is the largest volume of waste that is normally generated during oil and gas production. It has large amounts of contaminants that can cause negative environmental and economic impacts. The management method for PW relies highly on types and concentrations of these contaminants, which are field dependent and can vary from one oil field to another. Produced water can be converted to fresh water if these contaminants are removed or reduced to the acceptable drinking water...
Show moreProduced Water (PW) is the largest volume of waste that is normally generated during oil and gas production. It has large amounts of contaminants that can cause negative environmental and economic impacts. The management method for PW relies highly on types and concentrations of these contaminants, which are field dependent and can vary from one oil field to another. Produced water can be converted to fresh water if these contaminants are removed or reduced to the acceptable drinking water quality level. In addition, increasing oil production rate and reducing amounts of discharged harmful contaminants can be achieved by removing dissolved hydrocarbons from PW. In order to identify the types of these contaminants, effective tools and methods should be used. Six Sigma, which uses the DMAIC (Define- Measure- Analyze- Improve- Control) problem-solving approach is one of the most effective tools to identify the root causes of having high percentages of contaminants in produced water. The methodology also helped develop a new policy change for implementing a way by which this treated water may be used. Six Sigma has not been widely implemented in oil and gas industries. This research adopted the Six Sigma methodology through a case study, related to the southern Iraqi oil fields, to investigate different ways by which produced water can be treated. Research results showed that the enormous amount of contaminated PW could be treated by using membrane filtration technology. In addition, a Multi Criteria Decision Making (MCDM) framework is developed and that could be used as an effective tool for decision makers. The developed framework could be used within manufacturing industries, services, educational systems, governmental organizations, and others.
Show less - Date Issued
- 2013
- Identifier
- CFE0004645, ucf:49904
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004645
- Title
- Using Technology in the Treatment of Selective Mutism: The Incorporation of Mobile Applications.
- Creator
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Bunnell, Brian, Beidel, Deborah, Rapport, Mark, Neer, Sandra, Hundley, Gulnora, University of Central Florida
- Abstract / Description
-
Selective mutism (SM) is a diagnosis marked by withdrawal of speech in certain social situations. The treatment of SM is often a difficult and lengthy process and there are many barriers to successful intervention. Behavioral therapy is most effective in the treatment of SM and the addition of therapeutic activities such as games and mobile devices may provide distinct advantages to this treatment (i.e., decreased patient anxiety levels and more active engagement). The current investigation...
Show moreSelective mutism (SM) is a diagnosis marked by withdrawal of speech in certain social situations. The treatment of SM is often a difficult and lengthy process and there are many barriers to successful intervention. Behavioral therapy is most effective in the treatment of SM and the addition of therapeutic activities such as games and mobile devices may provide distinct advantages to this treatment (i.e., decreased patient anxiety levels and more active engagement). The current investigation examined the utility of mobile applications during the behavioral treatment of SM as well as the effect of using mobile applications on child-reported and physiological indicators of anxious responding. Results indicated that children made remarkable treatment gains in just two treatment sessions (i.e., spoke to the clinician within 22 minutes of treatment and held five, five-minute conversations with additional adults during a second session) regardless of modality of delivery (using mobile applications, other activities, or reinforcement alone). Children shaped to speak with the inclusion of mobile applications reported less anxiety and exhibited decreased physiological anxious distress during treatment. The utility of mobile applications during the treatment of SM is discussed in addition to areas for future research (e.g., mobile-based treatment dissemination initiatives).
Show less - Date Issued
- 2015
- Identifier
- CFE0005767, ucf:50087
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005767
- Title
- Applications of Artificial Intelligence in Military Simulation.
- Creator
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Golovcsenko, Igor V., Biegel, John E., Engineering
- Abstract / Description
-
University of Central Florida College of Engineering Thesis; This report is a survey of Artificial Intelligence (AI) technology contributions to military training. It provides an overview of military training simulation and a review of instructional problems and challenges which can be addressed by AI. The survey includes current as well as potential applications of AI, with particular emphasis on design and system integration issues. Applications include knowledge and skills training in...
Show moreUniversity of Central Florida College of Engineering Thesis; This report is a survey of Artificial Intelligence (AI) technology contributions to military training. It provides an overview of military training simulation and a review of instructional problems and challenges which can be addressed by AI. The survey includes current as well as potential applications of AI, with particular emphasis on design and system integration issues. Applications include knowledge and skills training in strategic planning and decision making, tactical warfare operations, electronics maintenance and repair, as well as computer-aided design of training systems. The report describes research contributions in the application of AI technology to the training world, and it concludes with an assessment of future research directions in this area.
Show less - Date Issued
- 1987
- Identifier
- CFR0011599, ucf:53044
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0011599
- Title
- AGEIST PERCEPTIONS IN PERSONNEL SELECTION DECISIONS: A PREJUDICE-REDUCTION INTERVENTION.
- Creator
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Marcus, Justin, Fritzsche, Barbara, University of Central Florida
- Abstract / Description
-
The purpose of the current study was to examine whether older job applicants are discriminated against relative to younger job applicants when changing careers, and to investigate whether an intervention designed to reduce stereotyping and prejudice could alleviate such unfair discrimination, if it was found. A between-subjects laboratory experiment with three factors was conducted, including age (young vs. old job applicant), career-transition type (within- vs. between-career transition),...
Show moreThe purpose of the current study was to examine whether older job applicants are discriminated against relative to younger job applicants when changing careers, and to investigate whether an intervention designed to reduce stereotyping and prejudice could alleviate such unfair discrimination, if it was found. A between-subjects laboratory experiment with three factors was conducted, including age (young vs. old job applicant), career-transition type (within- vs. between-career transition), and a dual-identity based recategorization intervention (control vs. intervention), totaling 8 experimental conditions. Data were collected and analyzed from 157 undergraduate student participants. Participants were informed that they would be evaluating the viability of using video-resumes as a potential organizational selection tool, and were randomly assigned to watch a video-resume depicting a White male job applicant applying for the job of mechanical engineer. The job applicant was either younger or older and was either making a career change that was more similar to his previous career (i.e., naval architect) or less similar to his previous career (i.e., chiropractor). In the intervention conditions, the job applicant emphasized his age and the fact that he graduated from UCF; in the control conditions, he only emphasized his age and his educational background from a generic university. An actor in his early twenties played the role of the job applicant. Make-up was applied to age his face, and computer software was used to age his voice. After viewing the video-resumes, participants judged his suitability for hire, competence, warmth, loyalty, and suitability for training. A Multivariate Analysis of Covariance (MANCOVA) was conducted and a significant 3-way interaction was found between age, career-transition type, and intervention on both ratings of suitability for hire and on competence ratings. Counter to theory, the older job applicant was negatively impacted relative to the younger applicant when attempting to build a common ingroup identity with the younger decision-maker. These findings were discussed within the context of theories on attribution and impression management, and discussed relative to prior research utilizing the dual-identity based recategorization intervention method. Implications for older workers making career transitions are discussed.
Show less - Date Issued
- 2010
- Identifier
- CFE0003324, ucf:48450
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003324
- Title
- INTEGRATING UNIVERSAL DESIGN FOR LEARNING THROUGH CONTENT VIDEO WITH PRESERVICE TEACHERS.
- Creator
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Aronin, Sara, Dieker, Lisa, University of Central Florida
- Abstract / Description
-
Given current legislation to ensure education for students with disabilities and that institutions of higher education are required to use universal design for learning (UDL) principles, the purpose of this study was to explore the impact of video modeling on preservice teachers' knowledge, understanding and application of the three principles of UDL. Preservice teachers were randomly assigned to control or experimental groups to determine if video embedded with UDL principles impacted...
Show moreGiven current legislation to ensure education for students with disabilities and that institutions of higher education are required to use universal design for learning (UDL) principles, the purpose of this study was to explore the impact of video modeling on preservice teachers' knowledge, understanding and application of the three principles of UDL. Preservice teachers were randomly assigned to control or experimental groups to determine if video embedded with UDL principles impacted their thinking. Specifically, pre and posttest information of knowledge and understanding as well as self-perceived ability to teach students with disabilities using UDL was analyzed. In addition preservice teacher created lesson plans were analyzed for application of UDL principles after viewing the video intervention. Quantitative analyses were conducted to compare pre and posttest scores of the control group (n = 41) and experimental group (n =45). The quantitative analyses of knowledge, understanding and self-perceived ability to use UDL were mixed. The results of this investigation were consistent with current research that teacher application of a skill requires more than a one-shot intervention.
Show less - Date Issued
- 2009
- Identifier
- CFE0002816, ucf:48115
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002816
- Title
- Pervasive Secure Content Delivery Networks Implementation.
- Creator
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Lugo-Cordero, Hector, Guha, Ratan, Stanley, Kenneth, Chatterjee, Mainak, Wu, Annie, Lu, Kejie, University of Central Florida
- Abstract / Description
-
Over the years, communication networks have been shifting their focus from providing connectivity in a client/server model to providing a service or content. This shift has led to topic areas like Service-Oriented Architecture (SOA), Heterogeneous Wireless Mesh Networks, and Ubiquitous Computing. Furthermore, probably the broadest of these areas which embarks all is the Internet of Things (IoT). The IoT is defined as an Internet where all physical entities (e.g., vehicles, appliances, smart...
Show moreOver the years, communication networks have been shifting their focus from providing connectivity in a client/server model to providing a service or content. This shift has led to topic areas like Service-Oriented Architecture (SOA), Heterogeneous Wireless Mesh Networks, and Ubiquitous Computing. Furthermore, probably the broadest of these areas which embarks all is the Internet of Things (IoT). The IoT is defined as an Internet where all physical entities (e.g., vehicles, appliances, smart phones, smart homes, computers, etc.), which we interact daily are connected and exchanging data among themselves and users. The IoT has become a global goal for companies, researchers, and users alike due to its different implementation and functional benefits: performance efficiency, coverage, economic and health. Due to the variety of devices which connect to it, it is expected that the IoT is composed of multiple technologies interacting together, to deliver a service. This technologies interactions renders an important challenge that must be overcome: how to communicate these technologies effectively and securely? The answer to this question is vital for a successful deployment of IoT and achievement of all the potential benefits that the IoT promises.This thesis proposes a SOA approach at the Network Layer to be able to integrate all technologies involved, in a transparent manner. The proposed set of solutions is composed of primarily the secure implementation of a unifying routing algorithm and a layered messaging model to standardizecommunication of all devices. Security is targeted to address the three main security concerns (i.e., confidentiality, integrity, and availability), with pervasive schemes that can be employed for any kind of device on the client, backbone, and server side. The implementation of such schemes is achieved by standard current security mechanisms (e.g., encryption), in combination with novel context and intelligent checks that detect compromised devices. Moreover, a decentralized content processing design is presented. In such design, content processing is handled at the client side, allowing server machines to serve more content, while being more reliable and capable of processing complete security checks on data and client integrity.
Show less - Date Issued
- 2017
- Identifier
- CFE0006620, ucf:51268
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006620
- Title
- Development of Molecularly Imprinted Polymers for Forensic Applications.
- Creator
-
Martinez, Sara, Sigman, Michael, Bridge, Candice, Yestrebsky, Cherie, University of Central Florida
- Abstract / Description
-
In some forensic disciplines various methods of extraction are used to perform analysis. Among these methods, solid phase extraction (SPE) and solid phase microextraction (SPME) are used in fields such as toxicology and explosives analysis. To enhance extraction efficiency in SPE and SPME, molecularly imprinted polymers (MIPs), which are designer polymers, can be more selective for the binding of an analyte or group of analytes that are similarly structured. Separation of analytes from...
Show moreIn some forensic disciplines various methods of extraction are used to perform analysis. Among these methods, solid phase extraction (SPE) and solid phase microextraction (SPME) are used in fields such as toxicology and explosives analysis. To enhance extraction efficiency in SPE and SPME, molecularly imprinted polymers (MIPs), which are designer polymers, can be more selective for the binding of an analyte or group of analytes that are similarly structured. Separation of analytes from complex mixtures is possible by utilizing these polymers. This may be especially useful in forensic applications where sample sizes may be small and composition may be complex. In this work, MIP solid phase microextraction fibers (MIP-SPME) were fabricated and caffeine was selectively sampled in the presence of theophylline and theobromine. Calibration studies were performed using the MIP-SPME to quantitate the concentration of caffeine in teas and coffees. MIP-SPME fibers were also prepared with 2,4-dinitrotoluene and deuterated 2,6-dinitrotoluene. Less selectivity was obtained for extraction of 2,4-DNT and 2,6-DNT in the presence of other DNT isomers. Fabricated blank polymers extracted analytes at the same response as templated polymers for both caffeine and DNT, despite expected results. MIP-SPE columns were also fabricated using deuterated 2,6-DNT to determine if changing the extraction procedure would increase extraction selectivity. Using different solvents in the extraction procedure changed the extraction performance efficiency of the MIPs due to the change in solvent polarity. All samples were analyzed using gas chromatography mass spectrometry.
Show less - Date Issued
- 2016
- Identifier
- CFE0006477, ucf:51423
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006477
- Title
- Modeling User Transportation Patterns Using Mobile Devices.
- Creator
-
Davami, Erfan, Sukthankar, Gita, Gonzalez, Avelino, Foroosh, Hassan, Sukthankar, Rahul, University of Central Florida
- Abstract / Description
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Participatory sensing frameworks use humans and their computing devices as a large mobile sensing network. Dramatic accessibility and affordability have turned mobile devices (smartphone and tablet computers) into the most popular computational machines in the world, exceeding laptops. By the end of 2013, more than 1.5 billion people on earth will have a smartphone. Increased coverage and higher speeds of cellular networks have given these devices the power to constantly stream large amounts...
Show moreParticipatory sensing frameworks use humans and their computing devices as a large mobile sensing network. Dramatic accessibility and affordability have turned mobile devices (smartphone and tablet computers) into the most popular computational machines in the world, exceeding laptops. By the end of 2013, more than 1.5 billion people on earth will have a smartphone. Increased coverage and higher speeds of cellular networks have given these devices the power to constantly stream large amounts of data.Most mobile devices are equipped with advanced sensors such as GPS, cameras, and microphones. This expansion of smartphone numbers and power has created a sensing system capable of achieving tasks practically impossible for conventional sensing platforms. One of the advantages of participatory sensing platforms is their mobility, since human users are often in motion. This dissertation presents a set of techniques for modeling and predicting user transportation patterns from cell-phone and social media check-ins. To study large-scale transportation patterns, I created a mobile phone app, Kpark, for estimating parking lot occupancy on the UCF campus. Kpark aggregates individual user reports on parking space availability to produce a global picture across all the campus lots using crowdsourcing. An issue with crowdsourcing is the possibility of receiving inaccurate information from users, either through error or malicious motivations. One method of combating this problem is to model the trustworthiness of individual participants to use that information to selectively include or discard data.This dissertation presents a comprehensive study of the performance of different worker quality and data fusion models with plausible simulated user populations, as well as an evaluation of their performance on the real data obtained from a full release of the Kpark app on the UCF Orlando campus. To evaluate individual trust prediction methods, an algorithm selection portfolio was introduced to take advantage of the strengths of each method and maximize the overall prediction performance.Like many other crowdsourced applications, user incentivization is an important aspect of creating a successful crowdsourcing workflow. For this project a form of non-monetized incentivization called gamification was used in order to create competition among users with the aim of increasing the quantity and quality of data submitted to the project. This dissertation reports on the performance of Kpark at predicting parking occupancy, increasing user app usage, and predicting worker quality.
Show less - Date Issued
- 2015
- Identifier
- CFE0005597, ucf:50258
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005597
- Title
- Influence of Task-Role Mental Models on Human Interpretation of Robot Motion Behavior.
- Creator
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Ososky, Scott, Jentsch, Florian, Shumaker, Randall, Fiore, Stephen, Lackey, Stephanie, University of Central Florida
- Abstract / Description
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The transition in robotics from tools to teammates has begun. However, the benefit autonomous robots provide will be diminished if human teammates misinterpret robot behaviors. Applying mental model theory as the organizing framework for human understanding of robots, the current empirical study examined the influence of task-role mental models of robots on the interpretation of robot motion behaviors, and the resulting impact on subjective ratings of robots. Observers (N = 120) were exposed...
Show moreThe transition in robotics from tools to teammates has begun. However, the benefit autonomous robots provide will be diminished if human teammates misinterpret robot behaviors. Applying mental model theory as the organizing framework for human understanding of robots, the current empirical study examined the influence of task-role mental models of robots on the interpretation of robot motion behaviors, and the resulting impact on subjective ratings of robots. Observers (N = 120) were exposed to robot behaviors that were either congruent or incongruent with their task-role mental model, by experimental manipulation of preparatory robot task-role information to influence mental models (i.e., security guard, groundskeeper, or no information), the robot's actual task-role behaviors (i.e., security guard or groundskeeper), and the order in which these robot behaviors were presented. The results of the research supported the hypothesis that observers with congruent mental models were significantly more accurate in interpreting the motion behaviors of the robot than observers without a specific mental model. Additionally, an incongruent mental model, under certain circumstances, significantly hindered an observer's interpretation accuracy, resulting in subjective sureness of inaccurate interpretations. The strength of the effects that mental models had on the interpretation and assessment of robot behaviors was thought to have been moderated by the ease with which a particular mental model could reasonably explain the robot's behavior, termed mental model applicability. Finally, positive associations were found between differences in observers' interpretation accuracy and differences in subjective ratings of robot intelligence, safety, and trustworthiness. The current research offers implications for the relationships between mental model components, as well as implications for designing robot behaviors to appear more transparent, or opaque, to humans.
Show less - Date Issued
- 2013
- Identifier
- CFE0005391, ucf:50457
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005391
- Title
- Analysis, Design and Efficiency Optimization of Power Converters for Renewable Energy Applications.
- Creator
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Chen, Xi, Batarseh, Issa, Zhou, Qun, Mikhael, Wasfy, Sun, Wei, Kutkut, Nasser, University of Central Florida
- Abstract / Description
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DC-DC power converters are widely used in renewable energy-based power generation systems due to the constant demand of high-power density and high-power conversion efficiency. DC-DC converters can be classified into non-isolated and isolated topologies. For non-isolated topologies, they are typically derived from buck, boost, buck-boost or forth order (such as Cuk, Sepic and Zeta) converters and they usually have relatively higher conversion efficiency than isolated topologies. However, with...
Show moreDC-DC power converters are widely used in renewable energy-based power generation systems due to the constant demand of high-power density and high-power conversion efficiency. DC-DC converters can be classified into non-isolated and isolated topologies. For non-isolated topologies, they are typically derived from buck, boost, buck-boost or forth order (such as Cuk, Sepic and Zeta) converters and they usually have relatively higher conversion efficiency than isolated topologies. However, with the applications where the isolation is required, either these topologies should be modified, or alternative topologies are needed. Among various isolated DC-DC converters, the LLC resonant converter is an attractive selection due to its soft switching, isolation, wide gain range, high reliability, high power density and high conversion efficiency.In low power applications, such as battery chargers and solar microinverters, increasing the switching frequency can reduce the size of passive components and reduce the current ripple and root-mean-square (RMS) current, resulting in higher power density and lower conduction loss. However, switching losses, gate driving loss and electromagnetic interference (EMI) may increase as a consequence of higher switching frequency. Therefore, switching frequency modulation, components optimization and soft switching techniques have been proposed to overcome these issues and achieve a tradeoff to reach the maximum conversion efficiency.This dissertation can be divided into two categories: the first part is focusing on the well-known non-isolated bidirectional cascaded-buck-boost converter, and the second part is concentrating on the isolated dual-input single resonant tank LLC converter. Several optimization approaches have been presented to improve the efficiency, power density and reliability of the power converters. In the first part, an adaptive switching frequency modulation technique has been proposed based on the precise loss model in this dissertation to increase the efficiency of the cascaded-buck-boost converter. In adaptive switching frequency modulation technique, the optimal switching frequency for the cascaded-buck-boost converter is adaptively selected to achieve the minimum total power loss. In addition, due to the major power losses coming from the inductor, a new low profile nanocrystalline inductor filled with copper foil has been designed to significantly reduce the core loss and winding loss. To further improve the efficiency of the cascaded-buck-boost converter, the adaptive switching frequency modulation technique has been applied on the converter with designed nanocrystalline inductor, in which the peak efficiency of the converter can break the 99% bottleneck.In the second part, a novel dual-input DC-DC converter is developed according to the LLC resonant topology. This design concept minimizes the circuit components by allowing single resonant tank to interface with multiple input sources. Based on different applications, the circuit configuration for the dual-input LLC converter will be a little different. In order to improve the efficiency of the dual-input LLC converter, the semi-active rectifiers have been used on the transformer secondary side to replace the low-side bridge diodes. In this case, higher magnetizing inductance can be selected while maintaining the same voltage gain. Besides, a burst-mode control strategy has been proposed to improve the light load and very light load efficiency of the dual- input LLC converter. This control strategy is able to be readily implemented on any power converter since it can be achieved directly through firmware and no circuit modification is needed in implementation of this strategy.
Show less - Date Issued
- 2019
- Identifier
- CFE0007612, ucf:52531
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007612
- Title
- Examining the Effects of Interactive Dynamic Multimedia and Direct Touch Input on Performance of a Procedural Motor Task.
- Creator
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Marraffino, Matthew, Sims, Valerie, Chin, Matthew, Mouloua, Mustapha, Johnson, Cheryl, University of Central Florida
- Abstract / Description
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Ownership of mobile devices, such as tablets and smartphones, has quickly risen in the last decade. Unsurprisingly, they are now being integrated into the training and classroom setting. Specifically, the U.S. Army has mapped out a plan in the Army Learning Model of 2015 to utilize mobile devices for training purposes. However, before these tools can be used effectively, it is important to identify how the tablets' unique properties can be leveraged. For this dissertation, the touch interface...
Show moreOwnership of mobile devices, such as tablets and smartphones, has quickly risen in the last decade. Unsurprisingly, they are now being integrated into the training and classroom setting. Specifically, the U.S. Army has mapped out a plan in the Army Learning Model of 2015 to utilize mobile devices for training purposes. However, before these tools can be used effectively, it is important to identify how the tablets' unique properties can be leveraged. For this dissertation, the touch interface and the interactivity that tablets afford were investigated using a procedural-motor task. The procedural motor task was the disassembly procedures of a M4 carbine. This research was motivated by cognitive psychology theories, including Cognitive Load Theory and Embodied Cognition. In two experiments, novices learned rifle disassembly procedures in a narrated multimedia presentation presented on a tablet and then were tested on what they learned during the multimedia training involving a virtual rifle by performing a rifle disassembly on a physical rifle, reassembling the rifle, and taking a written recall test about the disassembly procedures. Spatial ability was also considered as a subject variable.Experiment 1 examined two research questions. The primary research question was whether including multiple forms of interactivity in a multimedia presentation resulted in higher learning outcomes. The secondary research question in Experiment 1 was whether dynamic multimedia fostered better learning outcomes than equivalent static multimedia. To examine the effects of dynamism and interactivity on learning, four multimedia conditions of varying levels of interactivity and dynamism were used. One condition was a 2D phase diagram depicting the before and after of the step with no animation or interactivity. Another condition utilized a non-interactive animation in which participants passively watched an animated presentation of the disassembly procedures. A third condition was the interactive animation in which participants could control the pace of the presentation by tapping a button. The last condition was a rifle disassembly simulation in which participants interacted with a virtual rifle to learn the disassembly procedures. A comparison of the conditions by spatial ability yielded the following results. Interactivity, overall, improved outcomes on the performance measures. However, high spatials outperformed low spatials in the simulation condition and the 2D phase diagram condition. High spatials seemed to be able to compensate for low interactivity and dynamism in the 2D phase diagram condition while enhancing their performance in the rifle disassembly simulation condition.In Experiment 2, the touchscreen interface was examined by investigating how gestures and input modality affected learning the disassembly procedures. Experiment 2 had two primary research questions. The first was whether gestures facilitate learning a procedural-motor task through embodied learning. The second was whether direct touch input using resulted in higher learning outcomes than indirect mouse input. To examine the research questions, three different variations of the rifle disassembly simulation were used. One was identical to that of Experiment 1. Another incorporated gestures to initiate the animation whereby participants traced a gesture arrow representing the motion of the component to learn the procedures. The third condition utilized the same interface as the initial rifle disassembly simulation but included (")dummy(") gesture arrows that displayed only visual information but did not respond to gesture. This condition was included to see the effects (if any) of the gesture arrows in isolation of the gesture component. Furthermore, direct touch input was compared to indirect mouse input. Once again, spatial ability also was considered. Results from Experiment 2 were inconclusive as no significant effects were found. This may have been due to a ceiling effect of performance. However, spatial ability was a significant predictor of performance across all conditions. Overall, the results of the two experiments support the use of multimedia on a tablet to train a procedural-motor task. In line with vision of ALM 2015, the research support incorporating tablets into U.S. Army training curriculum.
Show less - Date Issued
- 2014
- Identifier
- CFE0005376, ucf:50467
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005376
