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Title: A Retrospective Analysis and Field Study of Nanotechnology Related Ergonomic Risk in Industries Utilizing Nanomaterials.
Creator: Greaves-Holmes, Wanda, Mccauley Bush, Pamela, Mollaghasemi, Mansooreh, Sala-Diakanda, Serge, Raghavan, Seetha, Ahram, Tareq, University of Central Florida
Abstract / Description: The National Science Foundation estimates that two million skilled nanotechnology workers will be needed world wide by 2015 (-) one million of them in the United States (2001). In the absence of scientific clarity about the potential health effects of occupational exposure to nanoparticles, guidance in decision making about hazards, risk, and controls takes on new importance. Currently, guiding principles on personal protective equipment for workers who come in contact with nanomaterials have...
Show moreThe National Science Foundation estimates that two million skilled nanotechnology workers will be needed world wide by 2015 (-) one million of them in the United States (2001). In the absence of scientific clarity about the potential health effects of occupational exposure to nanoparticles, guidance in decision making about hazards, risk, and controls takes on new importance. Currently, guiding principles on personal protective equipment for workers who come in contact with nanomaterials have not been standardized universally. Utilizing the NASA-TLX, this dissertation investigates the adequacy and shortcomings of research efforts that seek to determine whether or not occupational exposure to nanomaterials while wearing personal protective equipment (PPE) is or is not potentially frustrating to the worker. While wearing PPE does the worker perceive additional effort, performance, physical, mental or temporal demands or are not impacted during task performance.
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Date Issued: 2012
Identifier: CFE0004497, ucf:49267
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004497

Title: DESIGN OF SILICON CONTROLLED RECTIFERS FOR ROBUST ELECTROSTATIC DISCHARGE PROTECTION APPLICATIONS.
Creator: Liu, Zhiwei, Liou, Juin J., University of Central Florida
Abstract / Description: Electrostatic Discharge (ESD) phenomenon happens everywhere in our daily life. And it can occurs through the whole lifespan of an Integrated Circuit (IC), from the early wafer fabrication process, extending to assembly operation, and finally ending at the user's site. It has been reported that up to 35% of total IC field failures are ESD-induced, with estimated annual costs to the IC industry running to several billion dollars. The most straightforward way to avoid the ICs suffering from the...
Show moreElectrostatic Discharge (ESD) phenomenon happens everywhere in our daily life. And it can occurs through the whole lifespan of an Integrated Circuit (IC), from the early wafer fabrication process, extending to assembly operation, and finally ending at the user's site. It has been reported that up to 35% of total IC field failures are ESD-induced, with estimated annual costs to the IC industry running to several billion dollars. The most straightforward way to avoid the ICs suffering from the threatening of ESD damages is to develop on-chip ESD protection circuits which can afford a robust, low-impedance bypassing path to divert the ESD current to the ground. There are three different types of popular ESD protection devices widely used in the industry, and they are diodes or diodes string, Grounded-gate NMOS (GGNMOS) and Silicon Controlled Rectifier (SCR). Among these different protection solutions, SCR devices have the highest ESD current conduction capability due to the conductivity modulation effect. But SCR devices also have several shortcomings such as the higher triggering point, the lower clamping voltage etc, which will become obstacles for SCR to be widely used as an ESD protection solutions in most of the industry IC products. At first, in some applications with pin voltage goes below ground or above the VDD, dual directional protection between each two pins are desired. The traditional dual-directional SCR structures will consume a larger silicon area or lead to big leakage current issue due to the happening of punch-through effect. A new and improved SCR structure for low-triggering ESD applications has been proposed in this dissertation and successfully realized in a BiCMOS process. Such a structure possesses the desirable characteristics of a dual-polarity conduction, low trigger voltage, small leakage current, large failing current, adjustable holding voltage, and compact size. Another issue with SCR devices is its deep snapback or lower holding voltage, which normally will lead to the latch-up happen. To make SCR devices be immunity with latch-up, it is required to elevate its holding voltage to be larger than the circuits operational voltage, which can be several tens volts in modern power electronic circuits. Two possible solutions have been proposed to resolve this issue. One solution is accomplished by using a segmented emitter topology based on the concept that the holding voltage can be increased by reducing the emitter injection efficiency. Experimental data show that the new SCR can posses a holding voltage that is larger than 40V and a failure current It2 that is higher than 28mA/um. The other solution is accomplished by stacking several low triggering voltage high holding voltage SCR cells together. The TLP measurement results show that this novel SCR stacking structure has an extremely high holding voltage, very small snapback, and acceptable failure current. The High Holding Voltage Figure of Merit (HHVFOM) has been proposed to be a criterion for different high holding voltage solutions. The HHVFOM comparison of our proposed structures and the existing high holding voltage solutions also show the advantages of our work.
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Date Issued: 2010
Identifier: CFE0003166, ucf:48616
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003166

Title: A Solid State Transducer for Monitoring Pipeline Cathodic Protection Voltages.
Creator: Bartell, Jon R., McCarter, Ed. R., Engineering
Abstract / Description: Florida Technological University College of Engineering Thesis
Date Issued: 1974
Identifier: CFR0011984, ucf:53094
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011984

Title: CRITICAL DIGITAL INFRASTRUCTURE PROTECTION: AN INVESTIGATOIN INTO THE INTERGOVERNMENTAL ACTIVITIES OF INFORMATION TECHNOLOGY DIRECTORS IN FLORIDA COUNTIES.
Creator: Devenny, Joah Nicole, Abel, Eileen, University of Central Florida
Abstract / Description: As cyber attacks become more sophisticated, the risk to all networked computer systems increases. Whether public or private, whether federal, state, or local, the threat is equally real. Consequently, local governments must respond accordingly to understand the threats, take measures to protect themselves, and determine how to respond in the event of a system breach. Additionally, since cyber criminals do not respect geographic or administrative boundaries, local leaders must be prepared to...
Show moreAs cyber attacks become more sophisticated, the risk to all networked computer systems increases. Whether public or private, whether federal, state, or local, the threat is equally real. Consequently, local governments must respond accordingly to understand the threats, take measures to protect themselves, and determine how to respond in the event of a system breach. Additionally, since cyber criminals do not respect geographic or administrative boundaries, local leaders must be prepared to instantly interact with other governments, agencies, and departments to suppress an attack.Guided by the theory of intergovernmental management (IGM), this exploratory research investigated how Information Technology (IT) Directors in Florida county constitutional offices use intergovernmental relations and management activities as part of their information security efforts. Specifically, this research sought to determine: 1) which IGM activities do county IT Directors most often perform; 2) do county IT Directors make more use of vertical or horizontal IGM relationships; 3) is there a relationship between office/county demographics and the IGM activities its IT Directors most often perform?To answer these questions, an electronic survey was distributed to 209 directors, of which 125 responded. Overwhelmingly, the findings indicate that these Directors rarely engage in IGM activities regardless of the purpose or type of government/department contacted. However, when seeking intergovernmental assistance, it is most often horizontally with other Departments within their own government and least often vertically with Federal offices. The most frequently performed intergovernmental activity is seeking technical assistance, however seeking program/project information is also perform more frequently than the other activities explored in this research. The least frequently performed activities involved seeking to modify established IT partnerships. Further, there was evidence of relationships between certain office/county demographics and IGM activity. The discovery of these patterns and relationships can be used to aid policy and program development, as well as to stimulate deeper inquiry into the intergovernmental dimensions involved in protecting local elements of the U.S. Critical Digital Infrastructure.
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Date Issued: 2004
Identifier: CFE0000059, ucf:46113
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000059

Title: EVALUATION OF SPACE SHUTTLE TILE SUBNOMINAL BONDS.
Creator: Snapp, Cooper, Moslehy, Faissal, University of Central Florida
Abstract / Description: This study researched the history of Space Shuttle Reusable Surface Insulation which was designed and developed for use on the United States Orbiter fleet to protect from the high heating experienced during reentry through Earth's atmosphere. Specifically the tile system which is attached to the structure by the means of an RTV adhesive has experienced situations where the bonds are identified as subnominal. The history of these subnominal conditions is presented along with a recent...
Show moreThis study researched the history of Space Shuttle Reusable Surface Insulation which was designed and developed for use on the United States Orbiter fleet to protect from the high heating experienced during reentry through Earth's atmosphere. Specifically the tile system which is attached to the structure by the means of an RTV adhesive has experienced situations where the bonds are identified as subnominal. The history of these subnominal conditions is presented along with a recent identification of a subnominal bond between the Strain Isolation Pad and the tile substrate itself. Tests were run to identify the cause of these subnominal conditions and also to show how these conditions were proved to be acceptable for flight. The study also goes into cases that could be used to identify subnominal conditions on tile as a non-destructive test prior to flight. Several options of non-destructive testing were identified and recommendations are given for future research into this topic. A recent topic is also discussed in the instance where gap fillers were identified during the STS-114 mission that did not properly adhere to the substrate. The gap fillers were found protruding past the Outer Mold Line of the vehicle which required an unprecedented spacewalk to remove them to allow for a safe reentry through the atmosphere.
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Date Issued: 2006
Identifier: CFE0000947, ucf:46754
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000947

Title: A MODEL OF LOW-RISK PIRACY.
Creator: Camilo, Amil, Burguet, Roberto, University of Central Florida
Abstract / Description: Heterogeneous consumers make the decision to buy a durable good or to download a replica, and a monopolist chooses to price and protect their intellectual property in the form of an authentication cost. An optimal price and authentication cost is derived, and shown to be higher than the efficient outcome for a uniform distribution of consumers. The optimal selection of price and protection are shown to be commensurate with his authenticating technology, and the searching ability of consumers....
Show moreHeterogeneous consumers make the decision to buy a durable good or to download a replica, and a monopolist chooses to price and protect their intellectual property in the form of an authentication cost. An optimal price and authentication cost is derived, and shown to be higher than the efficient outcome for a uniform distribution of consumers. The optimal selection of price and protection are shown to be commensurate with his authenticating technology, and the searching ability of consumers. As an extension, a layout for a monopolist problem where consumers have different searching abilities is shown to be indistinct from a homogeneous case when consumers are uniformly distributed.
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Date Issued: 2019
Identifier: CFH2000495, ucf:45647
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH2000495

Title: HIGH SCHOOL DROPOUT: A STUDY OF PARENTAL PERCEPTIONS OF DROPOUT AND PREVENTION STRATEGIES.
Creator: Garcia, Daniel, Mann, Mary, University of Central Florida
Abstract / Description: Dropping out from high school is becoming a growing trend that necessitates new and more powerful intervention strategies to be utilized. Large numbers of adolescents between the ages of 16- 24 have been shown to receive no high school diploma or equivalent. The effects of dropping out are far reaching, with many students who dropout facing depression and alienation that may lead to other negative consequences. This research focuses on the need for preventative action against the issue of...
Show moreDropping out from high school is becoming a growing trend that necessitates new and more powerful intervention strategies to be utilized. Large numbers of adolescents between the ages of 16- 24 have been shown to receive no high school diploma or equivalent. The effects of dropping out are far reaching, with many students who dropout facing depression and alienation that may lead to other negative consequences. This research focuses on the need for preventative action against the issue of dropout. One hypothesis to be tested is whether or not current dropout prevention techniques can be applied to students who are not at risk for dropping out. The researcher theorizes that if all students are exposed to these strategies then perhaps the overall school environment will yield less students who are at risk to begin with.
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Date Issued: 2013
Identifier: CFH0004481, ucf:45071
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004481

Title: Protective Behavioral Strategies and Alcohol-Related Sex Among College Students.
Creator: Peterson, Roselyn, Dvorak, Robert, Newins, Amie, Dunn, Michael, University of Central Florida
Abstract / Description: Adverse sexual outcomes (e.g., sexual regret, sexual risk, and sexual assault) are a common experience among college students. In particular, regretted sex is reported by a third of college students and may result in psychological harm. Previous literature has found that alcohol is involved in approximately one third of regretted sex experienced by college students. A gap exists in the literature identifying who is more susceptible to experiencing a regretted sexual experience. Previous...
Show moreAdverse sexual outcomes (e.g., sexual regret, sexual risk, and sexual assault) are a common experience among college students. In particular, regretted sex is reported by a third of college students and may result in psychological harm. Previous literature has found that alcohol is involved in approximately one third of regretted sex experienced by college students. A gap exists in the literature identifying who is more susceptible to experiencing a regretted sexual experience. Previous research has shown that students who implement protective behavioral strategies (PBS) while drinking are able to reduce alcohol-related negative consequences, including regretted sexual experiences. Three sub-types of PBS exist: Stopping/Limiting Drinking (SLD), Manner of Drinking (MD), and Serious Harm Reduction (SHR). The current study examines associations between regretted sexual experiences, alcohol use, and PBS. Participants were a sample of college students (n = 349) who completed a series of online surveys that assessed drinking habits, alcohol-related negative consequences (e.g., regretted sex), and PBS use. A multi-group path analysis (grouped by gender) found that alcohol use was positively associated with regretted sexual experiences. One of the three PBS sub-types, MD, was negatively associated with regretted sexual experiences. This association was mediated by alcohol use. A different PBS subtype, SHR, yielded a direct negative relationship with regretted sexual experiences for women, but not for men. Lastly, the interaction of SHR and alcohol use was significantly associated with regretted sexual experiences and varied by biological sex. Among women, low SHR potentiated the positive association between alcohol and regretted sex; in contrast, high SHR attenuated this association. In order to inform future interventions and subsequently decrease the number of alcohol-related negative consequences, further examination of differences in relationships between PBS subtypes, alcohol use, and regretted sex for men and women is warranted.
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Date Issued: 2019
Identifier: CFE0007706, ucf:52448
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007706

Title: QUERY PROCESSING IN LOCATION-BASED SERVICES.
Creator: Liu, Fuyu, Hua, Kien, University of Central Florida
Abstract / Description: With the advances in wireless communication technology and advanced positioning systems, a variety of Location-Based Services (LBS) become available to the public. Mobile users can issue location-based queries to probe their surrounding environments. One important type of query in LBS is moving monitoring queries over mobile objects. Due to the high frequency in location updates and the expensive cost of continuous query processing, server computation capacity and wireless communication...
Show moreWith the advances in wireless communication technology and advanced positioning systems, a variety of Location-Based Services (LBS) become available to the public. Mobile users can issue location-based queries to probe their surrounding environments. One important type of query in LBS is moving monitoring queries over mobile objects. Due to the high frequency in location updates and the expensive cost of continuous query processing, server computation capacity and wireless communication bandwidth are the two limiting factors for large-scale deployment of moving object database systems. To address both of the scalability factors, distributed computing has been considered. These schemes enable moving objects to participate as a peer in query processing to substantially reduce the demand on server computation, and wireless communications associated with location updates. In the first part of this dissertation, we propose a distributed framework to process moving monitoring queries over moving objects in a spatial network environment. In the second part of this dissertation, in order to reduce the communication cost, we leverage both on-demand data access and periodic broadcast to design a new hybrid distributed solution for moving monitoring queries in an open space environment. Location-based services make our daily life more convenient. However, to receive the services, one has to reveal his/her location and query information when issuing location-based queries. This could lead to privacy breach if these personal information are possessed by some untrusted parties. In the third part of this dissertation, we introduce a new privacy protection measure called query l-diversity, and provide two cloaking algorithms to achieve both location k-anonymity and query l-diversity to better protect user privacy. In the fourth part of this dissertation, we design a hybrid three-tier architecture to help reduce privacy exposure. In the fifth part of this dissertation, we propose to use Road Network Embedding technique to process privacy protected queries.
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Date Issued: 2010
Identifier: CFE0003487, ucf:48949
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003487

Title: ALTERNATIVE FOAM TREATMENTS FOR THE SPACE SHUTTLE'S EXTERNAL TANK.
Creator: Dreggors, Kirsten, Nayfeh, Jamal, University of Central Florida
Abstract / Description: The Space Shuttle Columbia accident and the recent excitement surrounding Discovery's return to space brought excessive media attention to the foam products used on the External Tank (ET). In both cases, videos showed chunks of foam or ablative material falling away from the ET during lift off. This led to several years of investigation and research into the exact cause of the accident and potential solutions to avoid the problem in the future. Several design changes were made prior to the...
Show moreThe Space Shuttle Columbia accident and the recent excitement surrounding Discovery's return to space brought excessive media attention to the foam products used on the External Tank (ET). In both cases, videos showed chunks of foam or ablative material falling away from the ET during lift off. This led to several years of investigation and research into the exact cause of the accident and potential solutions to avoid the problem in the future. Several design changes were made prior to the return to flight this year, but the ET still shed foam during lift off. Since the Columbia accident, the loss of foam on ETs has been a significant area of interest for NASA, United Space Alliance, and Lockheed Martin. The Columbia Accident Investigation Board did not evaluate alternative materials but certainly highlighted the need for change. The majority of the research previously concentrated on improving the design and/or the application process of the current materials. Within recent years, some research and testing has been done to determine if a glass microsphere composite foam would be an acceptable alternative, but this work was overcome by the need for immediate change to return the shuttle to flight in time to deliver supplies to the International Space Station. Through a better understanding of the foam products currently used on the ET, other products can be evaluated for future space shuttle flights and potential applications on new space vehicles. The material properties and the required functionality of alternative materials can be compared to the current materials to determine if suitable replacement products exist. This research also lends itself to the development of future space flight and unmanned launch vehicles. In this paper, the feasibility of alternative material for the space shuttle's external tank will be investigated. Research on what products are used on the ET and a set of functional requirements driving the selection of those materials will be presented. The material properties of the current ET foam products will be collected and an evaluation of how those materials' properties meet the functional requirements will be accomplished. Then significant research on polymeric foams and ablative materials will be completed to learn how these various products can be applied in this industry. With this research and analysis, the knowledge gained will be used to select and evaluate the effectiveness of an alternate product and to determine feasibility of a product change with the current ET and the importance of maintaining the shuttle launch schedule. This research will also be used to evaluate the potential application of the alternative product on future platforms. There are several possible outcomes to this research. This research could result in a recommended change to the ET foam material or a perfectly acceptable alternative material that could result in a cost or schedule impact if implemented. It is also possible that there exists no suitable alternative material given the existing functional requirements. In any case, the alternative material could have future applications on new space vehicles. A set of results from the research and analysis will be provided along with a recommendation on a future material for use on space vehicles.
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Date Issued: 2005
Identifier: CFE0000787, ucf:46566
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000787

Title: SOCIAL WORK STUDENTS' ATTITUDES AND PERCEPTIONS ABOUT THE AFFORDABLE CARE ACT.
Creator: Goddard, Yvichess, Burg, Mary Ann, University of Central Florida
Abstract / Description: The Affordable Care Act is creating major political changes, on the state and federal levels, and is redefining American citizens' ability to access health services. Medical and mental health social workers are in high demand within the health care workforce to advocate and assist patients in navigating through a complex health care system. Little research has been conducted in understanding future social work professionals' views and knowledge about the legislation. This exploratory...
Show moreThe Affordable Care Act is creating major political changes, on the state and federal levels, and is redefining American citizens' ability to access health services. Medical and mental health social workers are in high demand within the health care workforce to advocate and assist patients in navigating through a complex health care system. Little research has been conducted in understanding future social work professionals' views and knowledge about the legislation. This exploratory-descriptive study used a convenience sample of 105 Bachelors (BSW) and Masters (MSW) level social work students to explore views on health care policy and reform based on students' personal experiences accessing health care. The study also obtained an understanding of how demographic factors affect students' support for health reform. Implications of this study show the need for greater implementation of health policy education in the social work curriculum and further research on the factors affecting students' knowledge and attitudes of health reform.
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Date Issued: 2014
Identifier: CFH0004649, ucf:45306
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004649

Title: A NEW CRASH TEST: THE RISE AND FALL OF FLORIDA MOTOR VEHICLE NO-FAULT LAW.
Creator: Colquitt, James, Cook, Kathy, University of Central Florida
Abstract / Description: Florida is one of 12 states that have a no-fault law. The first party benefit coverage is known as personal injury protection (PIP). Every policy sold in the state must include at least $10,000 in personal injury protection. This law went into effect in 1971 and is now being challenged. Changes in consumer, lawyer, and doctor behavior as well as changes in the legal and economic environment have diminished the positive impact of the no-fault law. This thesis will focus on the diminished...
Show moreFlorida is one of 12 states that have a no-fault law. The first party benefit coverage is known as personal injury protection (PIP). Every policy sold in the state must include at least $10,000 in personal injury protection. This law went into effect in 1971 and is now being challenged. Changes in consumer, lawyer, and doctor behavior as well as changes in the legal and economic environment have diminished the positive impact of the no-fault law. This thesis will focus on the diminished effectiveness of the no-fault law in Florida. It will be based on research from primary sources. Other legal resources including law review articles and journal publications were consulted for persuasive scholarly views. Published work from insurance institutes and journals were included since they guide practitioners on the application of the law. Insurers, insureds and policymakers face serious challenges regarding Florida Motor Vehicle No-Fault Law. The purpose of this thesis is (1) to review the legislative history of Florida Motor Vehicle No-Fault Law, (2) to assess how well the current system is working (3) examine solutions to compensation from other states and provide relevant data and (4) make recommendations for future legislation. This thesis will recommend proposed changes with guidelines for future legislation to effect the changes necessary to balance the needs of the insurance companies, plaintiffs and defendants.
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Date Issued: 2014
Identifier: CFH0004558, ucf:45154
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004558

Title: SOCIAL WORK STUDENT PERCEPTIONS OF LABOR TRAFFICKING.
Creator: Mulhern, Margaret, Leon, Ana, University of Central Florida
Abstract / Description: Human Trafficking in Florida is a growing issue that affects individuals and communities on a micro, mezzo, and macro level. Although legislative efforts and changes in agency policies have raised awareness about this problem, limited awareness and research examines awareness of labor trafficking as one form of human trafficking. This exploratory-descriptive study used a convenience sampling technique to explore the perceptions of 45 Bachelors (BSW) and Masters (MSW) level social work...
Show moreHuman Trafficking in Florida is a growing issue that affects individuals and communities on a micro, mezzo, and macro level. Although legislative efforts and changes in agency policies have raised awareness about this problem, limited awareness and research examines awareness of labor trafficking as one form of human trafficking. This exploratory-descriptive study used a convenience sampling technique to explore the perceptions of 45 Bachelors (BSW) and Masters (MSW) level social work students on the prevalence and nature of labor trafficking. The findings from the research show students have a general idea of labor trafficking and believe in equal access to human rights for victims. However, majority of students were unaware of current legislation to aid victims in Florida, and the prevalence of men as victims. Implications from this study show a need for further education within social work policies that aid labor trafficking victims, and a need for additional research to identify specific ways students can learn about human trafficking.
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Date Issued: 2014
Identifier: CFH0004581, ucf:45202
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004581

Title: Seismic Response of Moment Resisting Frames Coupled with Rocking Walls.
Creator: Aghagholizadeh, Mehrdad, Makris, Nicos, Catbas, Necati, Mackie, Kevin, Kauffman, Jeffrey L., University of Central Florida
Abstract / Description: This study investigates the inelastic response of yielding structures coupled with rocking walls. This topic is of major significance in the design of tall moment-resisting buildings, since during recent major earthquakes several tall, moment-resisting frames that had been designed in an accordance to the existing seismic code provisions, exhibited a weak-story failure. Utilization of this structural system can help reducing maximum story drifts, prevents weak story failure and minimize...
Show moreThis study investigates the inelastic response of yielding structures coupled with rocking walls. This topic is of major significance in the design of tall moment-resisting buildings, since during recent major earthquakes several tall, moment-resisting frames that had been designed in an accordance to the existing seismic code provisions, exhibited a weak-story failure. Utilization of this structural system can help reducing maximum story drifts, prevents weak story failure and minimize residual deformation of the structure. This study first examines different configurations of both stepping rocking walls and pinned rocking walls that have been reported in the literature.Next, effect of additional vertical tendons or vertical damping devices in maximum response of the system is investigated. This research first derives the nonlinear equations of motion of a yieldingoscillator coupled with a rocking wall and the dependability of the one-degree of freedom idealization is validated against the nonlinear time-history response analysis of a 9-story moment-resisting frame coupled with a rocking wall. This research finally concludes that, stepping wall suppresses peak and permanent displacements, with the heavier wall being most effective. In contrast, the pinned rocking wall increases in general the peak inelastic displacements and the permanent displacements. While, the coupling of weak building frames with rocking walls is an efficient strategy that controls inelastic deformations by enforcing a uniform interstory-drift distribution, therefore, avoiding mid-story failures, the study shows that even for medium-rise buildings the effect of vertical tendons on the inelastic structural response is marginal, except for increasing the vertical reactions at the pivoting points of the rocking wall. Additionally, The SDOF idealization presented in this study compares satisfactory with finite-element analysis of a 9-story steel SAC building coupled with a stepping rocking wall; therefore, the SDOF idealization can be used with confidence for preliminary analysis and design.
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Date Issued: 2018
Identifier: CFE0007301, ucf:52157
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007301

Title: Threatening Instructions During a Hurricane Influence Risk Perceptions: The Case of Fear Appeals and Changing Hurricane Projections.
Creator: Whitmer, Daphne, Sims, Valerie, Chin, Matthew, Bowers, Clint, Kapucu, Naim, University of Central Florida
Abstract / Description: The goal of this research was to examine the effectiveness of persuasive language in the protective action recommendation of an emergency warning, which instructs people how to prepare and stay safe. Study 1 was a pilot study, which suggested that participants were able to make distinctions between hurricane categories. In study 2, the presence of fear language and second-person personal pronouns (i.e., (")you(")) in a recommendation was manipulated. Overall, fear language was more...
Show moreThe goal of this research was to examine the effectiveness of persuasive language in the protective action recommendation of an emergency warning, which instructs people how to prepare and stay safe. Study 1 was a pilot study, which suggested that participants were able to make distinctions between hurricane categories. In study 2, the presence of fear language and second-person personal pronouns (i.e., (")you(")) in a recommendation was manipulated. Overall, fear language was more influential than a pronoun on risk perceptions. To understand how context influences risk perceptions, participants in study 3 made decisions after each piece of information received. The severity of the hurricane increased, decreased, or stayed the same before decision point 2 and a recommendation containing fear or neutral language was presented before decision point 3. Those who read the fear message were more likely to be in the danger control process than those in the neutral language condition, which suggested that the fear message emphasized threat but did not diminish participants' perception of efficacy. Behavioral compliance with the warning was high in all conditions. In terms of change in perceived threat from decision point 2 to 3, participants in the decrease condition who read the fear appeal had the largest increase in perceived threat. In contrast, the hurricane increasing in intensity may be fear provoking enough that a fear appeal does not enhance risk perceptions. When examining individual differences, high Need for Cognition women had the largest increase in perceived message persuasiveness in the decrease and increase conditions.Phrasing guidelines for emergency management are discussed, along with the theoretical contributions of using social psychological methodology to examine emergency warnings. While individual differences are important predictors of warning interpretation, future research needs to reconcile the conundrum of emergency management's current limitations regarding individualized warnings.
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Date Issued: 2019
Identifier: CFE0007554, ucf:52611
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007554

Title: An Exploration of the Relationship between Work Climate, the Utilization of Support Resources, and Compassion Fatigue Level in Child Protective Investigators.
Creator: Holliker, Shannon, Leon, Ana, Yegidis, Bonnie, Dziegielewski, Sophia, Rosa-Lugo, Linda, University of Central Florida
Abstract / Description: The impact of child maltreatment is far reaching, affecting the abused child, the family system, and the professionals tasked with providing support during the moments of crisis. As child protective investigators (CPIs) provide care and support to others, they are at high risk of experiencing secondary traumatic stress and/or burnout, both aspects of compassion fatigue. Researchers suggest that work climate, utilization of resources, and worker characteristics can impact CPI compassion...
Show moreThe impact of child maltreatment is far reaching, affecting the abused child, the family system, and the professionals tasked with providing support during the moments of crisis. As child protective investigators (CPIs) provide care and support to others, they are at high risk of experiencing secondary traumatic stress and/or burnout, both aspects of compassion fatigue. Researchers suggest that work climate, utilization of resources, and worker characteristics can impact CPI compassion-fatigue level. Drawing on extant literature, this study examined three research questions and seven hypotheses aiming to explore the relationship between work climate, resource utilization, CPI characteristics, and CPI compassion-fatigue level. This dissertation research used a cross-sectional study design that included collecting data from 165 CPIs using three instruments: (a) CPI demographic form, (b) Professional Quality of Life-5, and (c) Safety Attitudes Questionnaire. Descriptive, nonparametric, and regression analyses were conducted on the returned surveys of 165 Florida-based CPIs. Results of data analyses indicated that statistically significant inverse relationships exist between the independent variable, compassion fatigue, and the dependent variables of teamwork climate, CPI supervision utilization, CPI age, and CPI trauma history (verbal abuse). The study presents implications for addressing compassion fatigue in CPIs from a public-affairs, a practice, and a research perspective.
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Date Issued: 2019
Identifier: CFE0007654, ucf:52496
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007654

Title: DESIGN OF LOW-CAPACITANCE AND HIGH-SPEED ELECTROSTATIC DISCHARGE (ESD) DEVICES FOR LOW-VOLTAGE PROTECTION APPLICATIONS.
Creator: Li, You, Liou, Juin J., University of Central Florida
Abstract / Description: Electrostatic discharge (ESD) is defined as the transfer of charge between bodies at different potentials. The electrostatic discharge induced integrated circuit damages occur throughout the whole life of a product from the manufacturing, testing, shipping, handing, to end user operating stages. This is particularly true as microelectronics technology continues shrink to nano-metric dimensions. The ESD related failures is a major IC reliability concern and results in a loss of millions...
Show moreElectrostatic discharge (ESD) is defined as the transfer of charge between bodies at different potentials. The electrostatic discharge induced integrated circuit damages occur throughout the whole life of a product from the manufacturing, testing, shipping, handing, to end user operating stages. This is particularly true as microelectronics technology continues shrink to nano-metric dimensions. The ESD related failures is a major IC reliability concern and results in a loss of millions dollars to the semiconductor industry each year. Several ESD stress models and test methods have been developed to reproduce the real world ESD discharge events and quantify the sensitivity of ESD protection structures. The basic ESD models are: Human body model (HBM), Machine model (MM), and Charged device model (CDM). To avoid or reduce the IC failure due to ESD, the on-chip ESD protection structures and schemes have been implemented to discharge ESD current and clamp overstress voltage under different ESD stress events. Because of its simple structure and good performance, the junction diode is widely used in on-chip ESD protection applications. This is particularly true for ESD protection of low-voltage ICs where a relatively low trigger voltage for the ESD protection device is required. However, when the diode operates under the ESD stress, its current density and temperature are far beyond the normal conditions and the device is in danger of being damaged. For the design of effective ESD protection solution, the ESD robustness and low parasitic capacitance are two major concerns. The ESD robustness is usually defined after the failure current It2 and on-state resistance Ron. The transmission line pulsing (TLP) measurement is a very effective tool for evaluating the ESD robustness of a circuit or single element. This is particularly helpful in characterizing the effect of HBM stress where the ESD-induced damages are more likely due to thermal failures. Two types of diodes with different anode/cathode isolation technologies will be investigated for their ESD performance: one with a LOCOS (Local Oxidation of Silicon) oxide isolation called the LOCOS-bound diode, the other with a polysilicon gate isolation called the polysilicon-bound diode. We first examine the ESD performance of the LOCOS-bound diode. The effects of different diode geometries, metal connection patterns, dimensions and junction configurations on the ESD robustness and parasitic capacitance are investigated experimentally. The devices considered are N+/P-well junction LOCOS-bound diodes having different device widths, lengths and finger numbers, but the approach applies generally to the P+/N-well junction diode as well. The results provide useful insights into optimizing the diode for robust HBM ESD protection applications. Then, the current carrying and voltage clamping capabilities of LOCOS- and polysilicon-bound diodes are compared and investigated based on both TCAD simulation and experimental results. Comparison of these capabilities leads to the conclusion that the polysilicon-bound diode is more suited for ESD protection applications due to its higher performance. The effects of polysilicon-bound diodeÃ‚Â's design parameters, including the device width, anode/cathode length, finger number, poly-gate length, terminal connection and metal topology, on the ESD robustness are studied. Two figures of merits, FOM_It2 and FOM_Ron, are developed to better assess the effects of different parameters on polysilicon-bound diodeÃ‚Â's overall ESD performance. As latest generation package styles such as mBGAs, SOTs, SC70s, and CSPs are going to the millimeter-range dimensions, they are often effectively too small for people to handle with fingers. The recent industry data indicates the charged device model (CDM) ESD event becomes increasingly important in todayÃ‚Â's manufacturing environment and packaging technology. This event generates highly destructive pulses with a very short rise time and very small duration. TLP has been modified to probe CDM ESD protection effectiveness. The pulse width was reduced to the range of 1-10 ns to mimic the very fast transient of the CDM pulses. Such a very fast TLP (VFTLP) testing has been used frequently for CDM ESD characterization. The overshoot voltage and turn-on time are two key considerations for designing the CDM ESD protection devices. A relatively high overshoot voltage can cause failure of the protection devices as well as the protected devices, and a relatively long turn-on time may not switch on the protection device fast enough to effectively protect the core circuit against the CDM stress. The overshoot voltage and turn-on time of an ESD protection device can be observed and extracted from the voltage versus time waveforms measured from the VFTLP testing. Transient behaviors of polysilicon-bound diodes subject to pulses generated by the VFTLP tester are characterized for fast ESD events such as the charged device model. The effects of changing devicesÃ‚Â' dimension parameters on the transient behaviors and on the overshoot voltage and turn-on time are studied. The correlation between the diode failure and poly-gate configuration under the VFTLP stress is also investigated. Silicon-controlled rectifier (SCR) is another widely used ESD device for protecting the I/O pins and power supply rails of integrated circuits. Multiple fingers are often needed to achieve optimal ESD protection performance, but the uniformity of finger triggering and current flow is always a concern for multi-finger SCR devices operating under the post-snapback region. Without a proper understanding of the finger turn-on mechanism, design and realization of robust SCRs for ESD protection applications are not possible. Two two-finger SCRs with different combinations of anode/cathode regions are considered, and their finger turn-on uniformities are analyzed based on the I-V characteristics obtained from the transmission line pulsing (TLP) tester. The dV/dt effect of pulses with different rise times on the finger turn-on behavior of the SCRs are also investigated experimentally. In this work, unless noted otherwise, all the measurements are conducted using the Barth 4002 transmission line pulsing (TLP) and Barth 4012 very-fast transmission line pulsing (VFTLP) testers.
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Date Issued: 2010
Identifier: CFE0003440, ucf:48401
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003440

Title: design, characterization and analysis of component level electrostatic discharge (esd) protection solutions.
Creator: Luo, Sirui, Liou, Juin, Yuan, Jiann-Shiun, Gong, Xun, Jin, Yier, Salcedo, Javier, University of Central Florida
Abstract / Description: Electrostatic Discharges (ESD) is a significant hazard to electronic components and systems. Based on a specific process technology, a given circuit application requires a customized ESD consideration that meets all the requirements such as the core circuit's operating condition, maximum accepted leakage current, breakdown conditions for the process and overall device sizes. In every several years, there will be a new process technology becomes mature, and most of those new technology...
Show moreElectrostatic Discharges (ESD) is a significant hazard to electronic components and systems. Based on a specific process technology, a given circuit application requires a customized ESD consideration that meets all the requirements such as the core circuit's operating condition, maximum accepted leakage current, breakdown conditions for the process and overall device sizes. In every several years, there will be a new process technology becomes mature, and most of those new technology requires custom design of effective ESD protection solution. And usually the design window will shrinks due to the evolving of the technology becomes smaller and smaller. The ESD related failure is a major IC reliability concern and results in a loss of millions dollars each year in the semiconductor industry. To emulate the real word stress condition, several ESD stress models and test methods have been developed. The basic ESD models are Human Body model (HBM), Machine Mode (MM), and Charge Device Model (CDM). For the system-level ESD robustness, it is defined by different standards and specifications than component-level ESD requirements. International Electrotechnical Commission (IEC) 61000-4-2 has been used for the product and the Human Metal Model (HMM) has been used for the system at the wafer level.Increasingly stringent design specifications are forcing original equipment manufacturers (OEMs) to minimize the number of off-chip components. This is the case in emerging multifunction mobile, industrial, automotive and healthcare applications. It requires a high level of ESD robustness and the integrated circuit (IC) level, while finding ways to streamline the ESD characterization during early development cycle. To enable predicting the ESD performance of IC's pins that are directly exposed to a system-level stress condition, a new the human metal model (HMM) test model has been introduced. In this work, a new testing methodology for product-level HMM characterization is introduced. This testing framework allows for consistently identifying ESD-induced failures in a product, substantially simplifying the testing process, and significantly reducing the product evaluation time during development cycle. It helps eliminates the potential inaccuracy provided by the conventional characterization methodology. For verification purposes, this method has been applied to detect the failures of two different products.Addition to the exploration of new characterization methodology that provides better accuracy, we also have looked into the protection devices itself. ICs for emerging high performance precision data acquisition and transceivers in industrial, automotive and wireless infrastructure applications require effective and ESD protection solutions. These circuits, with relatively high operating voltages at the Input/Output (I/O) pins, are increasingly being designed in low voltage Complementary Metal-Oxide-Semiconductor (CMOS) technologies to meet the requirements of low cost and large scale integration. A new dual-polarity SCR optimized for high bidirectional blocking voltages, high trigger current and low capacitance is realized in a sub 3-V, 180-nm CMOS process. This ESD device is designed for a specific application where the operating voltage at the I/O is larger than that of the core circuit. For instance, protecting high voltage swing I/Os in CMOS data acquisition system (DAS) applications. In this reference application, an array of thin film resistors voltage divider is directly connected to the interface pin, reducing the maximum voltage that is obtained at the core device input down to (&)#177; 1-5 V. Its ESD characteristics, including the trigger voltage and failure current, are compared against those of a typical CMOS-based SCR.Then, we have looked into the ESD protection designs into more advanced technology, the 28-nm CMOS. An ESD protection design builds on the multiple discharge-paths ESD cell concept and focuses the attention on the detailed design, optimization and realization of the in-situ ESD protection cell for IO pins with variable operation voltages. By introducing different device configurations fabricated in a 28-nm CMOS process, a greater flexibility in the design options and design trade-offs can be obtained in the proposed topology, thus achieving a higher integration and smaller cell size definition for multi-voltage compatibility interface ESD protection applications. This device is optimized for low capacitance and synthesized with the circuit IO components for in-situ ESD protection in communication interface applications developed in a 28-nm, high-k, and metal-gate CMOS technology.ESD devices have been used in different types of applications and also at different environment conditions, such as high temperature. At the last section of this research work, we have performed an investigation of several different ESD devices' performance under various temperature conditions. And it has been shown that the variations of the device structure can results different ESD performance, and some devices can be used at the high temperature and some cannot. And this investigation also brings up a potential threat to the current ESD protection devices that they might be very vulnerable to the latch-up issue at the higher temperature range.
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Date Issued: 2015
Identifier: CFE0005655, ucf:50189
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005655

Title: An Analysis of the Protected-Permitted Left Turn at Intersections with a Varying Number of Opposing Through Lanes.
Creator: Navarro, Alexander, Radwan, Essam, Abou-Senna, Hatem, Abdel-Aty, Mohamed, University of Central Florida
Abstract / Description: The Flashing Yellow Arrow Left Turn signal is quickly becoming prominent in Central Florida as a new method of handling left turns at traffic signals. While the concept of a protected-permitted left turn is not groundbreaking, the departure from the typical display of a five-section signal head is, for this type of operation. The signal head introduced is a four-section head with a flashing yellow arrow between the yellow and green arrows. With this signal head quickly becoming the standard,...
Show moreThe Flashing Yellow Arrow Left Turn signal is quickly becoming prominent in Central Florida as a new method of handling left turns at traffic signals. While the concept of a protected-permitted left turn is not groundbreaking, the departure from the typical display of a five-section signal head is, for this type of operation. The signal head introduced is a four-section head with a flashing yellow arrow between the yellow and green arrows. With this signal head quickly becoming the standard, there is a need to re-evaluate the operational characteristics of the left turning vehicle and advance the knowledge of the significant parameters that may affect the ability for a driver to make a left turn at a signalized intersection. With previous research into the behavioral and operational characteristics of the flashing yellow arrow conducted, there is more information becoming available about the differences between this signal and the previously accepted method of allowing left turns at an intersection. The protected-permitted signal is typically displayed at an intersection with up to two through lanes and generally a protected signal is installed when the number of through lanes increases above two unless specific criteria is met. With the advent of larger arterials and more traffic on the highway networks, the push to operate these intersections at their maximum efficiency has resulted in more of these protected-permitted signals being present at these larger intersections, including the flashing yellow arrow.The core of the research that follows is a comparative analysis of the operation and parameters that affect the left turn movement of the intersection with larger geometry to that of the smaller geometry. The significant parameters of the left turn movement were examined through means of collecting, organizing and analyzing just over 68 hours of field data. This research details the determining of the significant parameters based on the generation of a simulation model of the protected left turn using Synchro, a traffic simulation package, and regression models using field driven data to determine the significant parameters for predicting the number of left turns that can be made in the permitted phase under specific operating conditions. Intuitively, there is an expectation that a larger intersection will not allow for as many permitted lefts as a smaller intersection with all conditions remaining the same. The conclusions drawn from this analysis provide the framework to understanding the similarities and the differences that are encountered when the intersection geometry differs and help to more efficiently manage traffic at signalized intersections.The work of this field promises to enhance the operations of the left turning movement for traffic control devices. With an understanding of the statistical models generated, a broader base of knowledge is gained as to the significant parameters that affect a driver's ability to make the left turn. A discussion of the statistical differences and between the models generated from the small and large geometry intersections is critical to drive further research into standards being developed for the highway transportation network and the treatment of these large signalized intersections. The exploration of specific parameters to predict the number of permitted left turns will yield results as to if there is more to be considered with larger intersections moving forward as they become a standard sight on the roadway network.
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Date Issued: 2014
Identifier: CFE0005387, ucf:50440
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005387

Title: Evaluating the Effectiveness of Conversion of Traditional Five Section Head Signal to Flashing Yellow Arrow (FYA) Signal.
Creator: Almoshaogeh, Meshal, Radwan, Essam, Abdel-Aty, Mohamed, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: In the United States, there are two schemes of operating traffic signal controls for permitted protected left turns (PPLT) namely the traditional five-section head system (known as Dog-House) and the flashing yellow arrow system (FYA). Past studies have agreed that these controls lead to decrease the average delay per left turn vehicle, decrease the protected green time, increase the left turn capacity, and enhance the intersection overall operation.The flashing yellow arrow (FYA) has been...
Show moreIn the United States, there are two schemes of operating traffic signal controls for permitted protected left turns (PPLT) namely the traditional five-section head system (known as Dog-House) and the flashing yellow arrow system (FYA). Past studies have agreed that these controls lead to decrease the average delay per left turn vehicle, decrease the protected green time, increase the left turn capacity, and enhance the intersection overall operation.The flashing yellow arrow (FYA) has been approved by the Federal Highway Administration as the national standard for the PPLT operations at signalized intersections. So, the Florida Department of Transportation also approved this new system and they are extensively replacing the traditional system with the new system on the area of Central Florida (Lin, et al, 2010). Both these systems have been used for a long time and there are some studies that evaluated these systems but there are limited number of projects that evaluated and/or compared between the two PPLT systems from the operational perspective.The main goal of this research is to study the characteristics of traffic operations and evaluate the effectiveness of the conversion from five-section head signal to the FYA treatments at 13 intersections located in Orlando, Florida. To reach this goal, detailed data collection efforts were conducted at 13 selected intersections in the central Florida area and appropriate statistical tests were conducted using the Minitab 17 Software. Statistical tests were attempted to fit different new regression models that correlate delay and left turn volumes as response variables against a set of independent variables that included permitted green time, opposing volume, percent of trucks, time gaps, speed, and land use type. In addition to fitting the data to regression models, these models were also analyzed for the purpose of detecting any significant differences between the five-section head treatment and FYA treatment.The statistical differences of converting the five-section head system to FYA system were discussed. The results in this thesis agreed with some of the previous studies and did not agree with others. In general, the flashing yellow arrow system was found to enhance the intersection operation, increase the number of left turn vehicles, and reduce the delay. Also, some suggestions and recommendations were made based on this study results.
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Date Issued: 2014
Identifier: CFE0005296, ucf:50570
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005296

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