Doctor of Science in Engineering - Engineering / The advent of mobile technology, Geospatial Information Systems (GIS) and convergence of voice and data over wireless networks have led to an explosion of a wide range of mobile applications. These applications include mobile internet browsers, handheld GPS navigation systems, Location Based Services (LBS), mobile workforce management systems, and so on. While much of the underlying technology is already available, there are challenges with respect to the usability of mobile applications. This project investigates the usability of a mobile application for field data collection in a utility industry. The purpose of the investigation is to gain a better understanding of the usability requirements for a mobile field data collection application but more importantly, how to meet these requirements using appropriate usability engineering techniques. A usage-centered design approach is used to design the user interface for the field data collection application. During this model-driven design process, the usability requirements are analyzed in terms of the user requirements, field data collection tasks and the operational context of fieldwork. An Underground Utility Closure (UUC) data sourcing work employed at a telecommunications utility is used as a case study for the field data collection work. The user interface is implemented as a functional prototype on a pocket computer and evaluated for usability in a field setting. It is envisaged that the usability requirements and design guidelines presented in this project will enable software engineers to meet the design challenges of usable mobile applications for field data collection and mobile computing in general.

Blackberry (Rubus spp.) is a popular fruit due to its delightful taste and notable health benefits. With a growing demand for regional blackberry production, this study aims to provide Virginia blackberry growers with information on the effectiveness of pre-harvest foliar treatments and shade application on yield, white drupelet disorder, post-harvest attributes, and the aroma profile of two blackberry cultivars, Prime-Ark® Traveler and Prime-Ark® Freedom. The field study was repeated in the 2021 and 2022 growing seasons at the Hampton Roads Agricultural Research and Extension Center in Virginia Beach, VA, in a completely randomized design. Grower standard control (GSC), shade cloth with 30% light reduction (SHA), calcium (CAL), and salicylic acid (SAL) foliar applications were randomly assigned to each variety. Fruit yield and physicochemical attributes of the blackberry were collected and analyzed, and aroma-active compounds in blackberries were identified by use of headspace-solid-phase microextraction-gas chromatography-mass spectrometry-olfaction (HS-SPME-GC-MS-O). Shade cloth significantly reduced the white drupelet disorder (WDD) in Prime-Ark® Freedom but it also reduced the total soluble solid content (°Bx) and °Bx/% titratable acidity (a ratio indicates the sweet and sour balance for fruit) for both cultivars. No significant improvement was found in the TSS, TA, firmness and yield of blackberries treated with CAL and SAL. In total, 16 consistent aroma-active compounds were found across treatments for both varieties and growing seasons. Foliar and shade application did not alter the aroma profile of either blackberry cultivar. However, higher volatile contents were found in 2021 than in 2022, possibly due to climate variation. A clear distinction on aroma profiles of the above two cultivars were also observed: PrimeArk® Freedom was higher in compounds possessing "fruity" and "floral" notes, while PrimeArk® Traveler featured more "green" and "fresh" characteristics. Regional berry growers should be more conservative when adopting foliar and shade applications due to potential seasonal variations surpassing the significance of agronomic treatments. / Master of Science in Life Sciences / Blackberry (Rubus spp.) with its inky purple color, juicy bursts of sweet and tart flavor, and various health benefits has become more popular recently. With growing demands for locally produced blackberries with better flavor, this study will provide Virginia blackberry growers with information on the effectiveness of pre-harvest foliar treatments and shade applications on yield, white drupelet disorder, post-harvest attributes, and aroma profile of two blackberry cultivars, Prime-Ark® Traveler and Prime-Ark® Freedom. The field study was repeated for two growing seasons 2021 and 2022 at the Hampton Roads Agricultural Research and Extension Center in Virginia Beach, VA. All blackberry plants received standard fertigation, with plots receiving additional either calcium or salicylic acid foliar spray, or shade cloth (black mesh cloth) application to reduce 30% direct sunlight. Fruit yield and post-harvest attributes such as sugar content, firmness, phenolic content, and aroma of the Virginia-grown blackberries were studied. Shade cloth (light reduction) was effective in mitigating discoloration in Prime-Ark® Freedom, but it also reduced the sugar content and sweet and sour balance for both varieties. Calcium and salicylic acid were not effective in improving the yield and fruit quality of blackberries. Fruit harvested in 2021 had a more intense aroma and taste when compared to the 2022 season, likely due to the excessive heat and drier climate in year 2. The two cultivars have different aroma profiles, with PrimeArk® Freedom being more "fruity" and "floral" and PrimeArk® Traveler featuring more "green" and "fresh" notes. This study suggests that regional berry growers should be more conservative when adopting agronomic practices such as foliar spray and shade applications due to seasonal variations (temperature, rainfall) possibly surpassing the effectiveness of agronomic treatments.

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With the increasing number of transistors in the circuit, the time it requires to label the circuit as defect-free also increases. Test application time plays a major role in increasing yield in manufacturing. This thesis presents an approach to generate a test set to detect manufacturing faults considering the test application time. The test set is constructed using an initial compact test set and by utilizing the output signature of the test vectors and increasing the overlap with a succeeding test vector. The novelty of the approach is the consideration of the essential faults for the test generation of the optimal test vector and the distribution of those faults among other test vectors if such a test vector is not possible. The test generation of the optimal test vector is done using structural and SAT-based approach. The generated test set retains the fault coverage without any additional hardware overhead. The experimental results on the ISCAS89 benchmark circuit show significant reductions in the test application time.

The synthesis of novel polyurethanes for use in blood contacting applications was investigated. A series of polyurethanes containing biologically active groups in the hard segment was synthesized. Sulphonate-containing polyurethanes were produced using a sulphonated chain extender (biphenyl diamino disulphonic acid) and these polymers were subsequently reacted to incorporate arginine methyl ester groups via sulphonamide bonds. The novel polyurethanes were initially evaluated using elemental sulphur analysis and nitrogen analysis, gel permeation chromatography and Fourier transform infrared spectroscopy to verify reaction of the sulphonated chain extender and addition of arginine methyl ester. Three sulphonated polyurethanes covering a range of sulphonate content were produced by varying the prepolymer and hard segment lengths. These three polymers and the three corresponding arginine methyl ester containing polymers were characterized to relate both bulk and surface structure to physical and biological properties. Elemental analysis, gel permeation chromatography and Fourier transform infrared spectroscopy were used to characterize the molecular structure. These techniques provided results consistent with the expected reaction mechanisms. Electron spectroscopy for chemical analysis and contact angle measurements were used to analyse the surface structure. Preliminary contact angle data indicate that the sulphonated polyurethane surfaces are hydrophilic, but further investigation is required before a firm conclusion can be reached. ESCA results indicate that while soft segment surface enrichment is taking place there are significant numbers of sulphonate groups present at the polyurethane surface. Mechanically these polymers have similar ultimate tensile strength but lower elongation than polyurethanes produced using aliphatic diamines, like ethylene diamine. This is probably due to increased microphase segregation arising partly from incompatibility of the aromatic chain extender with the aliphatic soft segment and possibly partly to ion cluster formation. The incorporation of arginine methyl ester groups increases both the elongation and the tensile strength, probably due to reduced phase segregation. Fibrinogen adsorption experiments in plasma were conducted to evaluate the blood response of these polymers. The plasma adsorption "isotherms" for the novel polyurethanes do not show transient fibrinogen adsorption (Vroman effect) which has been observed on a number of other surfaces including a wide range of polyurethanes. Instead, the initially adsorbed fibrinogen remains adsorbed. Also the levels of fibrinogen adsorption from plasma are three to four times greater than observed on previously studied surfaces. Conversion of some of the sulphonate groups to sulphonamide-bonded arginine methyl ester restores the Vroman effect and results in lower levels of retained fibrinogen. These data suggest the possibility of a specific interaction between sulphonate groups and fibrinogen. / Thesis / Master of Engineering (ME)

In recent years, the sequential Monte Carlo method, also referred to as the particle filter has emerged as a powerful methodology for solving the generally difficult nonlinear, non-Gaussian optimal filtering problem. The underlying idea is to use a randomly weighted set of samples to recursively build in time, a point-mass approximation of the true posterior PDF. With this approximation, one can recursively estimate typically intractable posterior expectations of interest. Indeed, the PF can be applied to a very large class of models. Within the last few years, the aforementioned advantages have propelled research on particle filtering and its applications. The subject of this thesis is to the extend the theories and applications of the particle filter. The main contributions of this thesis are described as follows: 1. We consider the optimal filtering problem for a class of partially observed non-Gaussian dynamic state space models. In this class, the process equation consists of a combination of linear and nonlinear states, and the process noise for the nonlinear state update is a mixture of Gaussians. In order to solve this problem, we propose a novel method based on an efficient combination of the approximate conditional mean filter and the sequential importance sampling particle filter. 2. We address the problem of channel equalization and phase noise suppression in orthogonal frequency division multiplexing (OFDM) systems. For OFDM systems, random phase noise introduced by the local oscillator causes two effects: the common phase error (CPE), and the intercarrier interference (ICI). The performance of coherent OFDM systems greatly depends on the ability to accurately estimate the effective dynamic channel i.e., the combined effect of the CPE and the time-varying frequency selective channel. With this in mind, we propose an algorithm that equalizes in the frequency domain, and uses a pilot tone aided particle filter to track/estimate the effective dynamic channel in the time domain. To increase efficiency, we implement the particle filter via a combination of sequential importance sampling, Rao-Blackwellization, and strategies stemming from the auxiliary particle filter. / Thesis / Master of Applied Science (MASc)

This project is about a 3D graphics system for engineers and architects. Its goal is twofold: to provide tools for drawing 3D models, and to create a database support system where data related to these models would be stored (at present the first part has been implemented). Costs, materials, calculations of loads, stresses, and other important factors will be available to the user during the whole design process. The system will therefore allow for drawing realistic projects, not just conceptual visual models. The drawing tools provided by the system include a few drawing techniques and viewing functions. The system’s drawing routines operate on sets of points, lines, or components so that they are very fast and efficient. This approach to the method of drawing along with the description of the system are given in the following write-up. / Thesis / Master of Science (MS)

Master of Science / Department of Computing and Information Sciences / Daniel A. Andresen / Tutorials and Quiz Android Mobile application is an application which gives you brief tutorials on various programming languages and technologies to the user who has installed this application. It gives video tutorials and training on different technologies. The mobile application also contains sample code, interview questions, and answers. This application also conducts a quiz to the user who is interested in a particular technology for checking their knowledge on the subject. It has different levels like Basic Level and Advanced Level quiz. This application conducts a quiz in the form of multiple choice questions. After the completion of the quiz the application generates reports based on the quiz conducted. The user can also test their knowledge on those technologies based on a timed quiz, we can include the above technology questions in this application. We can give a time frame for each question and all the questions are to be answered in that specified time period. Say for example we can give 20 seconds to answer a question. If the user gives an incorrect answer, will be exited out of the quiz.

The booming mobile app market attracts a large number of developers. As a result, the competition is extremely tough. This fierce competition leads to high standards required for mobile apps, which mandates efficient and effective testing. Efficient testing requires little effort to use, while effective testing checks that the app under test behaves as expected. Manual testing is highly effective, but it is costly. Automatic testing should come to the rescue, but current automatic methods are either ineffective or inefficient. Methods using implicit specifications – for instance, “an app should not crash” for catching fail-stop errors – are ineffective because they cannot find semantic problems. Methods using explicit specifications such as test scripts are inefficient because they require huge developer effort to create and maintain specifications. In this thesis, we present our two approaches for solving these challenges. We first built the AppDoctor system which efficiently tests mobile apps. It quickly explores an app then slowly but accurately verifies the potential problems to identify bugs without introducing false positives. It uses dependencies discovered between actions to simplify its reports. Our second approach, implemented in the AppFlow system, leverages the ample opportunity of reusing test cases between apps to gain efficiency without losing effectiveness. It allows common UI elements to be used in test scripts then recognizes these UI elements in real apps using a machine learning approach. The system also allows tests to be specified in reusable pieces, and provides a system to synthesize complete test cases from these reusable pieces. It enables robust tests to be created and reused across apps in the same category. The combination of these two approaches enables a developer to quickly test an app on a great number of combinations of actions for fail-stop problems, and effortlessly and efficiently test the app on most common scenarios for semantic problems. This combination covers most of her test requirements and greatly reduces her burden in testing the app.