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Derivation of the Thematic Material and Intervallic Gestures From the Main Theme in Fantasia Carioca By Sérgio Assad (open access)

Derivation of the Thematic Material and Intervallic Gestures From the Main Theme in Fantasia Carioca By Sérgio Assad

The quantity of classical guitar literature reached a new peak late in the twentieth century with many famous guitarists publishing their own works for solo classical guitar. This increase in the published guitar literature resulted in a decline of the relative analytical discussions of contemporary guitar works. Sérgio Assad is a perfect example of an active guitarist/composer whose works are frequently performed in guitar recitals and yet very little discussion has been provided attempting to gain a deeper understanding of his compositional language. The purpose of this study is to two-fold: first, to show that Fantasia Carioca (1994) is a very carefully organized work and includes an intricate network of thematic material developed through a spectrum of intervallic gestures, of which all derive from the main theme of the piece; second, to provide a deeper insight into the compositional language of Sérgio Assad through a demonstration of different compositional procedures to which the composer resorts. This one-movement piece reveals a high level of organization present in Sérgio Assad's style. The entire thematic material is carefully derived from the main theme. Each thematic unit shows a set of predetermined characteristics that allow these units to react to particular textures and situations. …
Date: May 2013
Creator: Abdihodži?, Armin
System: The UNT Digital Library
Boosting for Learning From Imbalanced, Multiclass Data Sets (open access)

Boosting for Learning From Imbalanced, Multiclass Data Sets

In many real-world applications, it is common to have uneven number of examples among multiple classes. The data imbalance, however, usually complicates the learning process, especially for the minority classes, and results in deteriorated performance. Boosting methods were proposed to handle the imbalance problem. These methods need elongated training time and require diversity among the classifiers of the ensemble to achieve improved performance. Additionally, extending the boosting method to handle multi-class data sets is not straightforward. Examples of applications that suffer from imbalanced multi-class data can be found in face recognition, where tens of classes exist, and in capsule endoscopy, which suffers massive imbalance between the classes. This dissertation introduces RegBoost, a new boosting framework to address the imbalanced, multi-class problems. This method applies a weighted stratified sampling technique and incorporates a regularization term that accommodates multi-class data sets and automatically determines the error bound of each base classifier. The regularization parameter penalizes the classifier when it misclassifies instances that were correctly classified in the previous iteration. The parameter additionally reduces the bias towards majority classes. Experiments are conducted using 12 diverse data sets with moderate to high imbalance ratios. The results demonstrate superior performance of the proposed method compared …
Date: December 2013
Creator: Abouelenien, Mohamed
System: The UNT Digital Library
Qos Aware Service Oriented Architecture (open access)

Qos Aware Service Oriented Architecture

Service-oriented architecture enables web services to operate in a loosely-coupled setting and provides an environment for dynamic discovery and use of services over a network using standards such as WSDL, SOAP, and UDDI. Web service has both functional and non-functional characteristics. This thesis work proposes to add QoS descriptions (non-functional properties) to WSDL and compose various services to form a business process. This composition of web services also considers QoS properties along with functional properties and the composed services can again be published as a new Web Service and can be part of any other composition using Composed WSDL.
Date: August 2013
Creator: Adepu, Sagarika
System: The UNT Digital Library
Spatial Mismatch Between Hiv Infection and Access to Hiv Service Facilities in Texas (open access)

Spatial Mismatch Between Hiv Infection and Access to Hiv Service Facilities in Texas

Since 2004, the number of people living with HIV (PLWH) has steadily increased by about 5% and currently, the number in Texas is about 86,000. Though the National HIV/AIDS Strategic Plan seeks to ensure “unfettered access to quality healthcare”, barriers to access still exist especially among minority populations. This study examines the relationship between HIV infection rates and the geographic location of HIV service centers with a focus on 4 counties: namely, Dallas, Denton, Harris and Tarrant. The goal is to show whether there is a spatial mismatch between HIV rates and service providers. Are service facilities located in zip codes where they are most needed? Using the vulnerability framework and the Inverse Care Law (ICL), we address the research question using demographic variables (race/ethnicity, sex, poverty, education attainment) and HIV data. Our results show that extreme vulnerable zip codes have high HIV rates and closest proximity to HIV service providers.
Date: August 2013
Creator: Aggrey Korsah, Emmanuel
System: The UNT Digital Library
Energy Harvesting Wireless Piezoelectric Resonant Force Sensor (open access)

Energy Harvesting Wireless Piezoelectric Resonant Force Sensor

The piezoelectric energy harvester has become a new powering option for some low-power electronic devices such as MEMS (Micro Electrical Mechanical System) sensors. Piezoelectric materials can collect the ambient vibrations energy and convert it to electrical energy. This thesis is intended to demonstrate the behavior of a piezoelectric energy harvester system at elevated temperature from room temperature up to 82°C, and compares the system’s performance using different piezoelectric materials. The systems are structured with a Lead Magnesium Niobate-Lead Titanate (PMN-PT) single crystal patch bonded to an aluminum cantilever beam, Lead Indium Niobate-Lead Magnesium Niobate-Lead Titanate (PIN-PMN-PT) single crystal patch bonded to an aluminum cantilever beam and a bimorph cantilever beam which is made of Lead Zirconate Titanate (PZT). The results of this experimental study show the effects of the temperature on the operation frequency and output power of the piezoelectric energy harvesting system. The harvested electrical energy has been stored in storage circuits including a battery. Then, the stored energy has been used to power up the other part of the system, a wireless resonator force sensor, which uses frequency conversion techniques to convert the sensor’s ultrasonic signal to a microwave signal in order to transmit the signal wirelessly.
Date: December 2013
Creator: Ahmadi, Mehdi
System: The UNT Digital Library
The Effects of Adlerian Play Therapy on Maladaptive Perfectionism and Anxiety and in Children (open access)

The Effects of Adlerian Play Therapy on Maladaptive Perfectionism and Anxiety and in Children

I used singlecase A-B-A experimental design to examine the effectiveness of Adlerian play therapy (AdPT) for children identified with clinical levels of perfectionism on the Conners Parent Rating Scale-Revised and Conners Teacher Rating Scale-Revised. Participants were 2 children, a 10 year-old Hispanic male and a 7 year-old Caucasian female. To examine the effect of AdPT on maladaptive perfectionism and anxiety, the Child-Adolescent Perfectionism Scale and the Revised Children’s Manifest Anxiety Scale were administered to the children twice weekly over 3 phases of the study: baseline (6 administrations), intervention (12-16 administrations), and maintenance (6 administrations) for a total of 24 to 29 data points. Additionally, parents and teachers completed the Conners Rating Scales-Revised5 times: (1) prior to study, (2) following baseline/prior to treatment, (3) midpoint of treatment, (4) following treatment, and (5) following maintenance phase.During the intervention phase, the male and female participants attended 21 and 16 play therapy sessions, their mothers attended 6 and 5 parent consultations, and their teachers attended 6 and 3 teacher consultations, respectively. Analysis of the child self-report assessments indicated mixed and inconclusive results regarding the effects of AdPT on target behaviors. However, results of the parent and teacher reports indicated clinically significant reductionsin maladaptive perfectionism …
Date: August 2013
Creator: Akay, Sinem
System: The UNT Digital Library
Determination of Molecular Descriptors for Illegal Drugs by Gc-fid Using Abraham Solvation Model (open access)

Determination of Molecular Descriptors for Illegal Drugs by Gc-fid Using Abraham Solvation Model

The Abraham solvation parameter model is a good approach for analyzing and predicting biological activities and partitioning coefficients. The general solvation equation has been used to predict the solute property (SP) behavior of drug compounds between biological barriers. Gas chromatography (GC) retention time can be used to predict molecular descriptors, such as E, S, A, B & L for existing and newly developed drug compounds. In this research, six columns of different stationary phases were used to predict the Abraham molecular descriptors more accurately. The six stationary phases used were 5% phenylmethyl polysiloxane, 6% cyanopropylphenyl 94% dimethylpolysiloxane, 5% diphenyl 95% dimethylpolysiloxane, 100% dimethylpolysiloxane, polyethylene glycol and 35% diphenyl 65% dimethylpolysiloxane. Retention times (RT) of 75 compounds have been measured and logarithm of experimental average retention time Ln(RTexp) are calculated. The Abraham solvation model is then applied to predict the process coefficients of these compounds using the literature values of the molecular descriptors (Acree Compilation descriptors). Six correlation equations are built up as a training set for each of the six columns. The six equations are then used to predict the molecular descriptors of the illegal drugs as a test set. This work shows the ability to extract molecular information from …
Date: December 2013
Creator: Akhter, Syeda Sabrina
System: The UNT Digital Library
Evaluating Appropriateness of Emg and Flex Sensors for Classifying Hand Gestures (open access)

Evaluating Appropriateness of Emg and Flex Sensors for Classifying Hand Gestures

Hand and arm gestures are a great way of communication when you don't want to be heard, quieter and often more reliable than whispering into a radio mike. In recent years hand gesture identification became a major active area of research due its use in various applications. The objective of my work is to develop an integrated sensor system, which will enable tactical squads and SWAT teams to communicate when there is absence of a Line of Sight or in the presence of any obstacles. The gesture set involved in this work is the standardized hand signals for close range engagement operations used by military and SWAT teams. The gesture sets involved in this work are broadly divided into finger movements and arm movements. The core components of the integrated sensor system are: Surface EMG sensors, Flex sensors and accelerometers. Surface EMG is the electrical activity produced by muscle contractions and measured by sensors directly attached to the skin. Bend Sensors use a piezo resistive material to detect the bend. The sensor output is determined by both the angle between the ends of the sensor as well as the flex radius. Accelerometers sense the dynamic acceleration and inclination in 3 …
Date: May 2013
Creator: Akumalla, Sarath Chandra
System: The UNT Digital Library
The Effect of It Process Support, Process Visualization and Process Characteristics on Process Outcomes (open access)

The Effect of It Process Support, Process Visualization and Process Characteristics on Process Outcomes

Business process re-engineering (part of the Business Process Management domain) is among the top three concerns of Information Technology (IT) leaders and is deemed to be one of many important IT leveraging opportunities. Two major challenges have been identified in relation to BPM and the use of IT. The first challenge is related to involving business process participants in process improvement initiatives using BPM systems. BPM technologies are considered to be primarily targeted for developers and not BPM users, and the need to engage process participants into process improvement initiatives is not addressed, contributing to the business-IT gap. The second challenge is related to potential de-skilling of knowledge workers when knowledge-intensive processes are automated and process knowledge resides in IT, rather than human process participants. The two identified challenges are not separate issues. Process participants need to be knowledgeable about the process in order to actively contribute to BPM initiatives, and the loss of process knowledge as a result of passive use of automated systems may further threaten their participation in process improvement. In response to the call for more research on the individual impacts of business process initiatives, the purpose of this dissertation study is to understand the relationship …
Date: December 2013
Creator: Al Beayeyz, Alaa
System: The UNT Digital Library
3GPP Long Term Evolution LTE Scheduling (open access)

3GPP Long Term Evolution LTE Scheduling

Future generation cellular networks are expected to deliver an omnipresent broadband access network for an endlessly increasing number of subscribers. Long term Evolution (LTE) represents a significant milestone towards wireless networks known as 4G cellular networks. A key feature of LTE is the implementation of enhanced Radio Resource Management (RRM) mechanism to improve the system performance. The structure of LTE networks was simplified by diminishing the number of the nodes of the core network. Also, the design of the radio protocol architecture is quite unique. In order to achieve high data rate in LTE, 3rd Generation Partnership Project (3GPP) has selected Orthogonal Frequency Division Multiplexing (OFDM) as an appropriate scheme in terms of downlinks. However, the proper scheme for an uplink is the Single-Carrier Frequency Domain Multiple Access due to the peak-to-average-power-ratio (PAPR) constraint. LTE packet scheduling plays a primary role as part of RRM to improve the system’s data rate as well as supporting various QoS requirements of mobile services. The major function of the LTE packet scheduler is to assign Physical Resource Blocks (PRBs) to mobile User Equipment (UE). In our work, we formed a proposed packet scheduler algorithm. The proposed scheduler algorithm acts based on the number …
Date: December 2013
Creator: Alotaibi, Sultan
System: The UNT Digital Library
Novel Role of Trypsin in Zebrafish (open access)

Novel Role of Trypsin in Zebrafish

It has been shown previously in our laboratory that zebrafish produce trypsin from their gills when they are under stress, and this trypsin is involved in thrombocyte activation via PAR2 during gill bleeding. In this study, I investigated another role of the trypsin that is secreted from zebrafish. This investigation has demonstrated a novel role of trypsin in zebrafish. Not only did this investigation demonstrate the role of trypsin in zebrafish behavior, but also it showed that PAR2 might be the receptor that is involved in trypsin-mediated behavioral response. In addition, we have shown that Gq and ERK inhibitors are able to block the trypsin pathway and prevent the escaping behavior. Finally, the results of this investigation suggest that the cells that respond to trypsin are surface cells, which have an appearance similar to that of neuromast cells.
Date: May 2013
Creator: Alsrhani, Abdullah Falleh
System: The UNT Digital Library
Social Media in Policing: a Study of Dallas-fort Worth Area City Police Departments (open access)

Social Media in Policing: a Study of Dallas-fort Worth Area City Police Departments

Social media offers numerous opportunities to companies, organizations and government agencies to communicate with people outside their organization, to promote their interests and to better serve their customers, or as in the case with government agencies, to better serve their citizens. However, little is known about how police departments in particular use social media. This research study explores why police departments use social media, how they manage their social media tools, and the problems and challenges experienced as they use social media. This qualitative study is largely guided by grounded theory. The data were collected from a study population using local police departments in the Dallas-Fort worth (DFW) area principal cities using both individual interviews with police departments’ social media officers and observations of these departments’ online social media tools (in particular, Facebook and Twitter). This study has shown that the DFW area city police departments are using social media quite extensively to keep the public informed and often for investigative purposes. There are some success factors to adopting and using these tools, such as the motivation of department staff and their benefits, successful implementation of the tools, the simplicity of using tools and that it is absolutely free.
Date: August 2013
Creator: Altunbas, Fuat
System: The UNT Digital Library
The Extent of Autism Knowledge of Novice Alternatively Certified Special Education Teachers in Texas (open access)

The Extent of Autism Knowledge of Novice Alternatively Certified Special Education Teachers in Texas

An increase in the prevalence rate of autism is not necessarily matched by a concurrent increase in the rate of highly qualified special education teachers. The low ratio of highly qualified teachers to the number of students with autism has resulted in chronic teacher shortages in this area. Alternative certification is used as a mechanism to alleviate the demand for highly qualified teachers in special education. However, alternative certification routes have often left novice teachers underprepared for teaching students with autism, more specifically in the implementation of evidence-based practices necessary for instructional effectiveness. The purposes of the study were: a) to assess the knowledge of novice alternatively certified (AC) teachers in the area of autism education; and b) to determine the extent to which age, credit hours of instruction, formal hours of instruction, amount of professional development, and number of students with autism predict the variance in knowledge scores. Participants included all novice (i.e., first-and second-year) alternatively certified special education teachers in the state of Texas. Data were collected through an electronic survey instrument disseminated state-wide to approximately 33 individuals. Multiple regression was conducted in order to determine the strongest predictors of autism knowledge scores. In addition, a multi-way ANOVA …
Date: December 2013
Creator: Alward, Jennifer A.
System: The UNT Digital Library
Real-time Rendering of Burning Objects in Video Games (open access)

Real-time Rendering of Burning Objects in Video Games

In recent years there has been growing interest in limitless realism in computer graphics applications. Among those, my foremost concentration falls into the complex physical simulations and modeling with diverse applications for the gaming industry. Different simulations have been virtually successful by replicating the details of physical process. As a result, some were strong enough to lure the user into believable virtual worlds that could destroy any sense of attendance. In this research, I focus on fire simulations and its deformation process towards various virtual objects. In most game engines model loading takes place at the beginning of the game or when the game is transitioning between levels. Game models are stored in large data structures. Since changing or adjusting a large data structure while the game is proceeding may adversely affect the performance of the game. Therefore, developers may choose to avoid procedural simulations to save resources and avoid interruptions on performance. I introduce a process to implement a real-time model deformation while maintaining performance. It is a challenging task to achieve high quality simulation while utilizing minimum resources to represent multiple events in timely manner. Especially in video games, this overwhelming criterion would be robust enough to sustain …
Date: August 2013
Creator: Amarasinghe, Dhanyu Eshaka
System: The UNT Digital Library
A Performance Guide to Jean Balissat’s Kaleidoscope for Trumpet and Percussion (open access)

A Performance Guide to Jean Balissat’s Kaleidoscope for Trumpet and Percussion

Jean Balissat’s Kaleidoscope for trumpet and percussion is an important yet widely unknown piece within the trumpet repertoire. A comprehensive performance guide is necessary in order to overcome the musical and technical demands that this piece presents to the trumpeter. The first section of this document provides historical and contextual information about Jean Balissat, his compositional style, and relevant information regarding Kaleidoscope. The second section of this document includes a performance guide to the work. The third and final section provides the trumpet player with a pedagogical guide to performing this work. This guide includes background, contextual, and pedagogical information necessary for an informed and high-level performance.
Date: August 2013
Creator: Anderson, Matthew Douglas
System: The UNT Digital Library
Optical Transparent Pmma Composite Reinforced By Coaxial Electrospun Pan Hollow Nanofibers (open access)

Optical Transparent Pmma Composite Reinforced By Coaxial Electrospun Pan Hollow Nanofibers

Electrospinning has been recognized as an efficient technique for the fabrication of polymer fibers. These electrospun fibers have many applications across a broad range of industries. In this research, optical transparent composites were successfully fabricated by embedding polyacrylonitrile (PAN) hollow nanofibers into poly (methyl methacrylate) (PMMA) matrix. The hollow PAN nanofibers were prepared by coaxial electrospinning. The PAN was used as the shell solution, and the mineral oil was used as the core solution. The resulting fibers were then etched with octane to remove the mineral oil from the core. The hollow PAN fibers were then homogeneously distributed in PMMA resins to fabricate the composite. The morphology, transmittance and mechanical properties of the PAN/PMMA composite were then characterized with an ESEM, TEM, tensile testing machine, UV-vis spectrometer and KD2 Pro Decagon device. The results indicated that the hollow nanofibers have relatively uniform size with one-dimensional texture at the walls. The embedded PAN hollow nanofibers significantly enhanced the tensile stress and the Young's modulus of the composite (increased by 58.3% and 50.4%, respectively), while having little influence on the light transmittance of the composite. The KD2 Pro device indicated that the thermal conductivity of the PMMA was marginally greater than the …
Date: May 2013
Creator: Antoine, Donley
System: The UNT Digital Library
The Disney Influence on Kindergarten Girls' Body Image (open access)

The Disney Influence on Kindergarten Girls' Body Image

Media is now a part of the early childhood world. In many countries, including industrialized and developing countries, children spend more time consuming various kinds of media. The impact of media on children's perception of their body images has been and continues to be a concern of parents and early childhood professionals. This research examined the influence of Disney movies on Thai kindergarten girls' body images and self-esteem. Thai kindergarten girls completed three measures of body self-image: the Body Figure Preference Scale, the Body Esteem Scale, and the Self-Esteem Scale. The girl participants were randomly assigned to two groups: focused on a female theme (FFT) and focused on a non-human theme (FNT). The experimental group viewed "female" Disney movie themes, while the control group viewed "animal" Disney movie themes. Girls in the experimental group expressed greater body image dissatisfaction scores after watching Disney movies, which was an expected finding. Results from the present study suggest that girls in both groups become concerned about their body esteem after video exposure. However, there was no significant difference in self-esteem between girls in FFT and FNT. In summary, the findings of this study support the belief that Disney movies influence young girls' perceptions …
Date: May 2013
Creator: Asawarachan, Tanawan
System: The UNT Digital Library
Accuracy and Interpretability Testing of Text Mining Methods (open access)

Accuracy and Interpretability Testing of Text Mining Methods

Extracting meaningful information from large collections of text data is problematic because of the sheer size of the database. However, automated analytic methods capable of processing such data have emerged. These methods, collectively called text mining first began to appear in 1988. A number of additional text mining methods quickly developed in independent research silos with each based on unique mathematical algorithms. How good each of these methods are at analyzing text is unclear. Method development typically evolves from some research silo centric requirement with the success of the method measured by a custom requirement-based metric. Results of the new method are then compared to another method that was similarly developed. The proposed research introduces an experimentally designed testing method to text mining that eliminates research silo bias and simultaneously evaluates methods from all of the major context-region text mining method families. The proposed research method follows a random block factorial design with two treatments consisting of three and five levels (RBF-35) with repeated measures. Contribution of the research is threefold. First, the users perceived a difference in the effectiveness of the various methods. Second, while still not clear, there are characteristics with in the text collection that affect the …
Date: August 2013
Creator: Ashton, Triss A.
System: The UNT Digital Library
A Measurement of the Exclusive Branching Fraction for B \to pi K at BaBar (open access)

A Measurement of the Exclusive Branching Fraction for B \to pi K at BaBar

None
Date: June 11, 2013
Creator: Aspinwall, L.
System: The UNT Digital Library
Witchcraft: a Targeted Societal Discrimination Against Women in Northern Ghana (open access)

Witchcraft: a Targeted Societal Discrimination Against Women in Northern Ghana

A combination of aging and poverty is becoming dominant in African society today, at a time when African countries are expected to be recovering from poverty, and are projected to house the economic growth of the next century. The emergence of aging in African context and the aging of the world population will expose the weakness of the current mechanisms used for older people around the world. As economies grow around the world, the distribution gap between the affluent and the poor widens, and the constant struggles for wealth, power, and social status, amidst scarce resources, continue to be sustained. To remain in charge of economic resources, the powerful few devise means to disenfranchise the weak, and witchcraft accusation is one of such tools used in Northern Ghana today. A new wave of witchcraft accusation has caught the attention of many in Northern Ghana. These victims with certain socioeconomic characteristics appear helpless and without defense against such accusations. As a result, they suffer untold hardships and are often compelled to leave their homes and to reside in camps reserved for witches. This study was undertaken to identify those sociodemographic characteristics, which are commonly shared by witchcraft accusation victims. These sociodemographic …
Date: December 2013
Creator: Atumah, Oscar Nwagbo
System: The UNT Digital Library
Growing local foods movements: Farmers' markets as nodes for products and community in Dallas/Fort Worth (open access)

Growing local foods movements: Farmers' markets as nodes for products and community in Dallas/Fort Worth

Undergraduate thesis building on Feagan's (2007) analysis of ideas of community and place, and Kloppenburg et al.'s (1996) concept of foodsheds, and a modified form of drive-time polygons, termed 'marketsheds' that demarcate the consumer-draw area for farmers' markets. Specifically, the research analyzes the spatial distribution of local food communities in the Dallas-Fort Worth Metroplex (DFW) in Texas and links the foodshed concept to elements of community and sense of place. Two questions guide this study: 1) What are the characteristics of the DFW local foods movement? 2) How do local food producers create and conceptualize community and place?
Date: 2013~/2014~
Creator: Aucoin, Martin
System: The UNT Digital Library
Examining High School Coaches’ Likelihood to Refer To, Interest in Working With, and Plans to Hire a Sport Psychologist (open access)

Examining High School Coaches’ Likelihood to Refer To, Interest in Working With, and Plans to Hire a Sport Psychologist

The primary goal of the current study was to extend previous research suggesting that coaches are the primary gatekeepers who may be a barrier to working with athletes by examining high school coaches likelihood to refer to, interest in, and intention to hire a sport psychologist. Specifically, the current study examined relationships between high school coaches’ sex, age, and type of sport coached (i.e., contact vs. non-contact) and their likelihood to refer athletes to a sport psychologist for a variety of presenting issues (i.e., poor attentional focus, poor leadership, family issues, etc.). It also examined relationships between coaches’ sex, age, and type of sport coached (i.e., contact vs. non-contact) and their interest in working with a sport psychologist. Finally, the study examined reasons why coaches did not plan to hire a sport psychologist. An examination of the possible reasons that high school coaches do not plan to hire a sport psychologist served an exploratory purpose. Participants included 450 coaches who coached high school sports in the United States. Results indicated that female coaches and non-contact sport coaches were more likely to refer athletes to a sport psychologist for a variety of referral issues than male coaches and coaches of contact …
Date: December 2013
Creator: Austin, Harlan
System: The UNT Digital Library
Laser Deposition, Heat-treatment, and Characterization of the Binary Ti-xmn System (open access)

Laser Deposition, Heat-treatment, and Characterization of the Binary Ti-xmn System

The present research seeks to characterization of an additively manufactured and heat-treated Ti-xMn gradient alloy, a binary system that has largely been unexplored. In order to rapidly assess this binary system, compositionally graded Ti-xMn (0<x<15 wt%) specimens were fabricated using the LENS (Laser Engineered Net Shaping) and were subsequently heat-treated and characterized using a wide range of techniques. Microstructural changes with respect to the change in thermal treatments, hardness and chemical composition were observed and will be presented. These include assessments of both continuous cooling, leading to observations of both equilibrium and metastable phases, including the titanium martensites, and to direct aging studies looking for composition regimes that produce highly refined alpha precipitates – a subject of great interest given recent understandings of non-classical nucleation and growth mechanisms. The samples were characterized using SEM, EDS, TEM, and XRD and the properties probed using a Vickers Microhardness tester.
Date: August 2013
Creator: Avasarala, Chandana
System: The UNT Digital Library
Statistical Strategies for Efficient Signal Detection and Parameter Estimation in Wireless Sensor Networks (open access)

Statistical Strategies for Efficient Signal Detection and Parameter Estimation in Wireless Sensor Networks

This dissertation investigates data reduction strategies from a signal processing perspective in centralized detection and estimation applications. First, it considers a deterministic source observed by a network of sensors and develops an analytical strategy for ranking sensor transmissions based on the magnitude of their test statistics. The benefit of the proposed strategy is that the decision to transmit or not to transmit observations to the fusion center can be made at the sensor level resulting in significant savings in transmission costs. A sensor network based on target tracking application is simulated to demonstrate the benefits of the proposed strategy over the unconstrained energy approach. Second, it considers the detection of random signals in noisy measurements and evaluates the performance of eigenvalue-based signal detectors. Due to their computational simplicity, robustness and performance, these detectors have recently received a lot of attention. When the observed random signal is correlated, several researchers claim that the performance of eigenvalue-based detectors exceeds that of the classical energy detector. However, such claims fail to consider the fact that when the signal is correlated, the optimal detector is the estimator-correlator and not the energy detector. In this dissertation, through theoretical analyses and Monte Carlo simulations, eigenvalue-based detectors …
Date: December 2013
Creator: Ayeh, Eric
System: The UNT Digital Library