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A Preliminary Controller Design for Drone Carried Directional Communication System (open access)

A Preliminary Controller Design for Drone Carried Directional Communication System

In this thesis, we conduct a preliminary study on the controller design for directional antenna devices carried by drones. The goal of the control system is to ensure the best alignment between two directional antennas so as to enhance the performance of air-to-air communication between the drones. The control system at the current stage relies on the information received from GPS devices. The control system includes two loops: velocity loop and position loop to suppress wind disturbances and to assure the alignment of two directional antennae. The simulation and animation of directional antennae alignment control for two-randomly moving drones was developed using SIMULINK. To facilitate RSSI-based antenna alignment control to be conducted in the future work, a study on initial scanning techniques is also included at the end of this thesis.
Date: August 2015
Creator: AL-Emrani, Firas
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Constrained

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Glory Grab

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Illumination

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Limited Lesson

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Pastel Pink

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Pointe Shoes

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Power Punch

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library

Prayer Pose

Work of art of oil on canvas by artist Hannah Aaron as part of a 2020 MFA Exhibition, entitled "A Narrative Rewritten"
Date: 2019
Creator: Aaron, Hannah
Object Type: Artwork
System: The UNT Digital Library
My Whine, Your Wine (open access)

My Whine, Your Wine

Grapes hold the flavors of the lands where they grow, and when you make wine from them, those flavors of the land come through. Tasting wine from a place you've been can bring you back to that place with aromas and notes indicative of that place. A bottle of wine changes every day, and how it will taste depends on the moment you choose to release it from the glass walls. I have a vested interest in wine, because it is a living thing. I am compelled to make wine because its characteristics are like personality traits. Although some of those characteristics are harsh at times, I appreciate them all. Each trait plays an important role in the balance, the overall personality. Like my own personality flaws, wine's harsh tones can smooth over time. My relationship with wine is constantly evolving, with every new varietal, vintage, batch and blend. Believe me, after some of the jobs I had before my first day at Su Vino, I cherish every moment of my winemaking career. My Whine, Your Wine is the story of how it all started.
Date: December 2011
Creator: Abbott, Shannon Marie
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Field Validation of Zero Energy Lab Water-to-Water Ground Coupled Heat Pump Model (open access)

Field Validation of Zero Energy Lab Water-to-Water Ground Coupled Heat Pump Model

Heat pumps are a vital part of each building for their role in keeping the space conditioned for the occupant. This study focuses on developing a model for the ground-source heat pump at the Zero Energy lab at the University of North Texas, and finding the minimum data required for generating the model. The literature includes many models with different approaches to determine the performance of the heat pump. Each method has its pros and cons. In this research the equation-fit method was used to generate a model based on the data collected from the field. Two experiments were conducted for the cooling mode: the first one at the beginning of the season and the second one at the peak of the season to cover all the operation conditions. The same procedure was followed for the heating mode. The models generated based on the collected data were validated against the experiment data. The error of the models was within ±10%. The study showed that the error could be reduced by 20% to 42% when using the field data to generate the model instead of the manufacturer’s catalog data. Also it was found that the minimum period to generate the cooling …
Date: May 2016
Creator: Abdulameer, Saif
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Cognitive Engagement in Later Life: Descriptive and Explanatory Findings (open access)

Cognitive Engagement in Later Life: Descriptive and Explanatory Findings

Findings on the relationship between engagement in lifestyle and cognitive functioning are not consistent; some authors report that engagement in lifestyle predicts an individual's cognitive functioning; while other report that an individual's cognitive functioning predicts the type and level of engagement an individual participates in. The current study will use longitudinal data (N = 235) to investigate the bidirectional relationship between engagement (engaged lifestyle activities) and cognition (crystallized & fluid intelligence). Despite inconsistent findings it is proposed that cognitive functioning may be better understood when examining how stimulation of activity, need for cognition, and openness to experience affect engagement in an active lifestyle. As such the current study will investigate if stimulation of activity, need for cognition, and openness to experience moderate the relationship between engaged lifestyles and cognitive functioning. The results, limitations and implications are discussed.
Date: December 2016
Creator: Abdullah, Bashir
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Jacques-Antoine-Hippolyte, comte de Guibert: Father of the Grande Armée (open access)

Jacques-Antoine-Hippolyte, comte de Guibert: Father of the Grande Armée

The eighteenth century was a time of intense upheaval in France. The death of Louis XIV in 1715 and the subsequent reign of Louis XV saw the end of French political and martial hegemony on the continent. While French culture and language remained dominant in Europe, Louis XV's disinterested rule and military stagnation led to the disastrous defeat of the French army at the hands of Frederick the Great of Prussia in the Seven Years War (1756-1763). The battle of Rossbach marked the nadir of the French army in the Seven Years War. Frederick's army routed the French infantry that had bumbled its way into massed Prussian cavalry. Following the war, two reformist elements emerged in the army. Reformers within the government, chiefly Etienne François, duc de Choiseul, sought to rectify the army's poor performance and reconstitute France's military establishment. Outside the traditional army structure, military thinkers looked to military theory to reinvigorate the army from within and without. Foremost among the latter was a young officer named Jacques-Antoine-Hippolyte de Guibert, whose 1772 Essai général de tactique quickly became the most celebrated work of theory in European military circles. The Essai provided a new military constitution for France, proposing wholesale …
Date: May 2011
Creator: Abel, Jonathan, 1985-
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Master's Recital: 2017-03-20 – Kayla Abel, clarinet

Recital presented at the UNT College of Music Recital Hall in partial fulfillment of the Master of Music (MM) degree.
Date: March 20, 2017
Creator: Abel, Kayla
Object Type: Sound
System: The UNT Digital Library
Source Apportionment Analysis of Measured Volatile Organic Compounds in Corpus Christi, Texas (open access)

Source Apportionment Analysis of Measured Volatile Organic Compounds in Corpus Christi, Texas

Corpus Christi among of the largest industrialized coastal urban areas in Texas. The strategic location of the city along the Gulf of Mexico allows for many important industries and an international business to be located. The cluster of industries and businesses in the region contribute to the air pollution from emissions that are harmful to the environment and to the people living in and visiting the area. Volatile organic compounds (VOC) constitute an important class of pollutants measured in the area. The automated gas chromatography (Auto GC) data was collected from Texas Commission of Environmental Quality (TCEQ) and source apportionment analysis was conducted on this data to identify key sources of VOC affecting this study region. EPA PMF 3.0 was employed in this sources apportionment study of measured VOC concentration during 2005 - 2012 in Corpus Christi, Texas. The study identified nine optimal factors (Source) that could explain the concentration of VOC at two urbane monitoring sites in the study region. Natural gas was found to be the largest contributor of VOC in the area, followed by gasoline and vehicular exhaust. Diesel was the third highest contributor with emissions from manufacturing and combustion processes. Refineries gases and evaporative fugitive emissions …
Date: May 2014
Creator: Abood, Ahmed T.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications (open access)

Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications

Poor air quality can greatly affect the public health. Research studies indicate that indoor air can be more polluted than the outdoor air. An indoor air quality monitoring system will help to create an awareness of the quality of air inside which will eventually help in improving it. The objective of this research is to develop a low cost wireless sensor system for indoor air quality monitoring. The major cost reduction of the system is achieved by using low priced sensors. Interface circuits had to be designed to make these sensors more accurate. The system is capable of measuring carbon dioxide, carbon monoxide, ozone, temperature, humidity and volatile organic compounds. The prototype sensor node modules were developed. The sensor nodes were the connected together by Zigbee network. The nodes were developed in such a way that it is compact in size and wireless connection of sensor nodes enable to collect air quality data from multiple locations simultaneously. The collected data was stored in a computer. We employed linear least-square approach for the calibration of each sensor to derive a conversion formula for converting the sensor readings to engineering units. The system was tested with different pollutants and data collected was …
Date: May 2014
Creator: Abraham, Sherin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms (open access)

Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency …
Date: August 2010
Creator: Abtahi, Seyed Ali
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Integrating Selective Herbicide and Native Plant Restoration to Control Alternanthera philoxeroides (Alligator Weed) (open access)

Integrating Selective Herbicide and Native Plant Restoration to Control Alternanthera philoxeroides (Alligator Weed)

Exotic invasive aquatic weeds such as alligator weed (Alternanthera philoxeroides) threaten native ecosystems by interfering with native plant communities, disrupting hydrology, and diminishing water quality. Development of new tools to combat invaders is important for the well being of these sensitive areas. Integrated pest management offers managers an approach that combines multiple control methods for better control than any one method used exclusively. In a greenhouse and field study, we tested the effects of selective herbicide application frequency, native competitor plant introduction, and their integration on alligator weed. In the greenhouse study, alligator weed shoot, root, and total biomass were reduced with one herbicide application, and further reduced with two. Alligator weed cumulative stem length and shoot/root ratio was only reduced after two applications. In the greenhouse, introduction of competitors did not affect alligator weed biomass, but did affect shoot/root ratio. The interaction of competitor introduction and herbicide did not significantly influence alligator weed growth in the greenhouse study. In the field, alligator weed cover was reduced after one herbicide application, but not significantly more after a second. Introduction of competitor species had no effect on alligator weed cover, nor did the interaction of competitor species and herbicide application. This …
Date: December 2011
Creator: Adams, Justin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Increasing Exercise in Sedentary Adults Using a Contingency and Technology-Based Management Package to Begin and Sustain New Levels of Activity (open access)

Increasing Exercise in Sedentary Adults Using a Contingency and Technology-Based Management Package to Begin and Sustain New Levels of Activity

Using a multiple baseline across participants with a changing criterion, this study explored and evaluated the effects of the individualized contingency management package (goal-setting, education, etc.) with sedentary typical adults while focusing on the mentoring component and the use of the technology of the exercise tracker to increase and sustain physical exercise to a level that increased health-benefiting physical activity. During initial mentoring meeting prior to the start of baseline, each participant was given a Garmin Viovsmart 3® exercise tracker, educated on the basic components of the device, and connected to the dashboard through the Garmin Connect™ app on their smartphones. Once each participant's activity stabilized, participant began intervention with weekly mentoring meetings focused on immediate feedback (social reinforcement), goal-setting and education. Through the Connect™ app, experimenter gave social reinforcement on a VR3 schedule to each participant, and participants were encouraged to participate by commenting to other participants through a private group set up for this study. The results indicate that the individualized contingency management package was effective for three of four participants whom increased their total activity minutes from pre-intervention range 0-104 min of weekly activity to post-intervention range of 269-404 min weekly. The two participants that completed two- …
Date: August 2019
Creator: Adams, Kristen Lea
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Effects of Contingency Type on Accuracy and Reaction Time (open access)

The Effects of Contingency Type on Accuracy and Reaction Time

Positive and negative reinforcement contingencies have been compared in terms of preference, but the differential effects of positive and negative reinforcement on reaction time and accuracy with other variables controlled remain unclear. Fifteen undergraduate students participated in a sound discrimination task that involved random mixed-trial presentations of positive and negative reinforcement contingencies. The participants' goal was to correctly identify whether the tone was shorter or longer than 600 milliseconds. On positive reinforcement trials, the participants received feedback and money tallies only if they identified the sound length correctly, with each correct response in the positive reinforcement trials earning the participant 10 cents. On negative reinforcement trials, the participants received feedback and money tallies only if they identified the sound length incorrectly, with incorrect trials subtracting 10 cents from the participants' total money (which began at $4.00 to equalize the weights of the positive and negative reinforcement contingencies). Accuracy analyses showed a relatively curvilinear relationship between the number of errors for each participant and the binned duration of the sound stimulus, with no differences across the positive and negative reinforcement conditions. Results also indicated weak linear negative correlations at the single subject level between comparison stimulus duration and reaction time, with …
Date: August 2018
Creator: Adams, Owen James
Object Type: Thesis or Dissertation
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
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Determining the Emissivity of Roofing Samples: Asphalt, Ceramic and Coated Cedar (open access)

Determining the Emissivity of Roofing Samples: Asphalt, Ceramic and Coated Cedar

The goal is to perform heat measurements examine of selected roofing material samples. Those roofing materials are asphalt shingles, ceramics, and cedar. It’s important to understand the concept of heat transfer, which consists of conduction, convection, and radiation. Research work was reviewed on different infrared devices to see which one would be suitable for conducting my experiment. In this experiment, the main focus was on a specific property of radiation. That property is the emissivity, which is the amount of heat a material is able to radiate compared to a blackbody. An infrared measuring device, such as the infrared camera was used to determine the emissivity of each sample by using a measurement formula consisting of certain equations. These equations account for the emissivity, transmittance of heat through the atmosphere and temperatures of the samples, atmosphere and background. The experiment verifies how reasonable the data is compared to values in the emissivity table. A blackbody method such as electrical black tape was applied to help generate the correct data. With this data obtained, the emissivity was examined to understand what factors and parameters affect this property of the materials. This experiment was conducted using a suitable heat source to heat …
Date: December 2015
Creator: Adesanya, Oludamilola
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Knowledge Based System and Decision Making Methodologies in Materials Selection for Aircraft Cabin Metallic Structures (open access)

Knowledge Based System and Decision Making Methodologies in Materials Selection for Aircraft Cabin Metallic Structures

Materials selection processes have been the most important aspects in product design and development. Knowledge-based system (KBS) and some of the methodologies used in the materials selection for the design of aircraft cabin metallic structures are discussed. Overall aircraft weight reduction means substantially less fuel consumption. Part of the solution to this problem is to find a way to reduce overall weight of metallic structures inside the cabin. Among various methodologies of materials selection using Multi Criterion Decision Making (MCDM) techniques, a few of them are demonstrated with examples and the results are compared with those obtained using Ashby's approach in materials selection. Pre-defined constraint values, mainly mechanical properties, are employed as relevant attributes in the process. Aluminum alloys with high strength-to-weight ratio have been second-to-none in most of the aircraft parts manufacturing. Magnesium alloys that are much lighter in weight as alternatives to the Al-alloys currently in use in the structures are tested using the methodologies and ranked results are compared. Each material attribute considered in the design are categorized as benefit and non-benefit attribute. Using Ashby's approach, material indices that are required to be maximized for an optimum performance are determined, and materials are ranked based on the …
Date: August 2016
Creator: Adhikari, Pashupati Raj
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Solvent Effects and Bioconcentration Patterns of Antimicrobial Compounds in Wetland Plants (open access)

Solvent Effects and Bioconcentration Patterns of Antimicrobial Compounds in Wetland Plants

This study looked at effects of organic solvents dimethylsulfoxide, dimethylformamide and acetone at 0.01%, 0.05% and 0.1% concentration on germination and seedling development wetland plants. Even at 0.01% level, all solvents affected some aspect of seed germination or seedling growth. Acetone at 0.01% was least toxic. Root morphological characteristics were most sensitive compared to shoot morphological characteristics. This study also looked at bioconcentration patterns of antimicrobial compounds triclosan, triclocarban and methyl-triclosan in wetland plants exposed to Denton Municipal Waste Water Treatment Plant effluent. Bioconcentration patterns of antimicrobial compounds varied among species within groups as well as within organs of species. The highest triclocarban, triclosan and methyltriclosan concentration were in shoot of N. guadalupensis, root of N. lutea and in shoots of P. nodous respectively.
Date: May 2011
Creator: Adhikari, Sajag
Object Type: Thesis or Dissertation
System: The UNT Digital Library