Motion Coordination of Multiple Autonomous Vehicles in a Spatiotemporal Flowfield

The long-term goal of this research is to provide theoretically justified control strategies to operate autonomous vehicles in spatiotemporal flowfields. The specific objective of this dissertation is to use estimation and nonlinear control techniques to generate decentralized control algorithms that enable motion coordination for multiple autonomous vehicles while operating in a time-varying flowfield. A cooperating team of vehicles can benefit from sharing data and tasking responsibilities. Many existing control algorithms promote collaboration of autonomous vehicles. However, these algorithms often fail to account for the degradation of control performance caused by flowfields. This dissertation presents decentralized multivehicle coordination algorithms designed for operation in a spatially or temporally varying flowfield. Each vehicle is represented using a Newtonian particle traveling in a plane at constant speed relative to the flow and subject to a steering control. Initially, we assume the flowfield is known and describe algorithms that stabilize a circular formation in a time-varying spatially nonuniform flow of moderate intensity. These algorithms are extended by relaxing the assumption that the flow is known: the vehicles dynamically estimate the flow and use that estimate in the control. We propose a distributed estimation and control algorithm comprising a consensus filter to share information gleaned from noisy position measurements, and an information filter to reconstruct a spatially varying flowfield. The theoretical results are illustrated with numerical simulations of circular formation control and validated in outdoor unmanned aerial vehicle (UAV) flight tests

Enclosing a moving target with an optimally rotated and scaled multiagent pattern

We propose a novel control method to enclose a moving target in a two-dimensional setting with a team of agents forming a prescribed geometric pattern. The approach optimises a measure of the overall agent motion costs, via the minimisation of a suitably defined cost function encapsulating the pattern rotation and scaling. We propose two control laws which use global information and make the agents exponentially converge to the prescribed formation with an optimal scale that remains constant, while the team's centroid tracks the target. One control law results in a multiagent pattern that keeps a constant orientation in the workspace; for the other, the pattern rotates with constant speed. These behaviours, whose optimality and steadiness are very relevant for the task addressed, occur independently from the target's velocity. Moreover, the methodology does not require distance measurements, common coordinate references, or communications. We also present formal guarantees of collision avoidance for the proposed approach. Illustrative simulation examples are provided

Perceptions of the rules of business behaviour in the competitive banking environment in Uganda

Business rules shape the behaviour of a business and guide the behaviour of employees when conducting business. Therefore, business rules explain what is allowed and not allowed. It is argued that all organisations have business rules and engage in some form of relationship whether through competition or cooperation with other companies. In today’s business environment, organisations are embedded in relationships with other actors in order to gain access to resources that are needed. Therefore, each organisation’s business rules define their strategies and actions. The type of business rule behaviour which is applied by organisations encourages them to grow by taking market share from rivals or creating new markets. The aim of this study was to determine the influence of the rules of business behaviour on perceptions of the competitive banking environment in Uganda and its potential impact on certain outcomes. In this study, a quantitative research approach was adopted, as the study sought to investigate the relationships between variables. This study collected data through the use of a structured self-administered survey questionnaire which was distributed to 233 branches of banks in Uganda, totaling 700 bank employees. The survey yielded 529 usable questionnaires which were analyzed, using several statistical analysis techniques. A hypothetical model and measuring instrument of perceptions of the rules of business behaviour in the competitive banking environment within Uganda was developed. Six null-hypotheses were subjected to statistical analysis. The influence of three independent variables, namely, confrontational business behaviour, co-operational business behaviour and typologies of competition on the intermediate variable, perceptions of the competitive banking environment in Uganda were tested. The impact of these variables on three independent outcome variables, namely, organisational performance and customer loyalty and retention were also tested The empirical findings revealed that the rules of business behaviour have a significant relationship with perceptions of the competitive banking environment in Uganda. These results showed that confrontational behaviour as a rule of business behaviour can be classified as being direct or indirect. The study further revealed that banks should consider competitors as co-partners and not only as aggressors, indicating that co-operational business behaviour is statistically significantly related to perceptions of the competitive business environment in Uganda. The three typologies of competition, namely, defy attack, defense and debase attack are also positively related to perceptions of the competitive business environment in Uganda. The empirical results of the study also indicated that perceptions of the competitive banking environment have a positive relationship with outcomes such as organisational performance, customer retention and customer loyalty. This study contributed to the literature and body of knowledge regarding the impact of rules of business behaviour in the competitive banking environment in Uganda. This study could also assist banks, employees and customers alike to understand the different rules of business behaviour that exist and what strategies banks can employ to improve their position in the market. This study could also be replicated by other banks in other developing countries so as to ensure successful competition and the cooperation of banks as they engage in their activities in the banking industry

Calponin And Cytoskeleton Dynamics In Macrophage Functions And The Pathogenesis Of Atherosclerosis

Arterial atherosclerosis is an inflammatory disease. Macrophages play a major role in the pathogenesis and progression of atherosclerotic lesions. Modulation of macrophage function is a therapeutic target for the treatment of atherosclerosis. Calponin is an actin-filament-associated regulatory protein that inhibits the activity of myosin-ATPase and dynamics of the actin cytoskeleton. Encoded by the Cnn2 gene, calponin isoform 2 is expressed at significant levels in macrophages. Deletion of calponin 2 increases macrophage migration and phagocytosis. In the present study, we investigated the effect of deletion of calponin 2 in macrophages on the pathogenesis and development of atherosclerosis. The results showed that macrophages isolated from Cnn2 knockout mice ingested the same level of acetylated low-density lipoprotein (LDL) as that of wild type (WT) macrophages but the resulting foam cells had significantly less impaired velocity of migration. Systemic or myeloid cell-specific Cnn2 knockouts effectively attenuated the development of arterial atherosclerosis lesions with less macrophage infiltration in apolipoprotein E knockout mice. Consistently, calponin 2-null macrophages produced less pro-inflammatory cytokines than that of WT macrophages, and the up-regulation of pro-inflammatory cytokines in foam cells was also attenuated by the deletion of calponin 2. Calponin 2-null macrophages and foam cells have significantly weakened cell adhesion, indicating a role of cytoskeleton regulation in macrophage functions and inflammatory responses, and a novel therapeutic target for the treatment of arterial atherosclerosis

THE USE OF REGRESSION MODELS FOR DETECTING DIGITAL FINGERPRINTS IN SYNTHETIC AUDIO

Modern advancements in text to speech and voice conversion techniques make it increasingly difficult to distinguish an authentic voice from a synthetically generated voice. These techniques, though complex, are relatively easy to use, even for non-technical users. It is important to develop mechanisms for detecting false content that easily scale to the size of the monitoring requirement. Current approaches for detecting spoofed audio are difficult to scale because of their processing requirements. Individually analyzing spectrograms for aberrations at higher frequencies relies too much on independent verification and is more resource intensive. Our method addresses the resource consideration by only looking at the residual differences between an audio file’s smoothed signal and its actual signal. We conjecture that natural audio has greater variance than spoofed audio because spoofed audio’s generation is conditioned on trying to mimic an existing pattern. To test this, we develop a classifier that distinguishes between spoofed and real audio by analyzing the differences in residual patterns between audio files.Outstanding ThesisMajor, United States ArmyApproved for public release. Distribution is unlimited

Ecological Risk Assessment for the State-wide Small Pelagic Scalefish Resource

In July 2021, the Department of Primary Industries and Regional Development convened an ecological risk assessment (ERA) of the fisheries that access the State-wide Small Pelagic Scalefish Resource. The ERA considered the potential ecological impacts of the West Coast Purse Seine Fishery, South Coast Purse Seine Fishery, Purse Seine Development Zones and the recreational fishers who catch small pelagic scalefish. The assessment evaluated the impact of each fishing sector/method on all relevant retained and bycatch species, endangered, threatened and protected species, habitats and the broader environment

On the development of a cybernetic prosthetic hand

The human hand is the end organ of the upper limb, which in humans serves the important function of prehension, as well as being an important organ for sensation and communication. It is a marvellous example of how a complex mechanism can be implemented, capable of realizing very complex and useful tasks using a very effective combination of mechanisms, sensing, actuation and control functions. In this thesis, the road towards the realization of a cybernetic hand has been presented. After a detailed analysis of the model, the human hand, a deep review of the state of the art of artificial hands has been carried out. In particular, the performance of prosthetic hands used in clinical practice has been compared with the research prototypes, both for prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by comparing the characteristics of these hands with the natural model, the human hand, the limitations of current artificial devices will be put in evidence, thus outlining the design goals for a new cybernetic device. Three hand prototypes with a high number of degrees of freedom have been realized and tested: the first one uses microactuators embedded inside the structure of the fingers, and the second and third prototypes exploit the concept of microactuation in order to increase the dexterity of the hand while maintaining the simplicity for the control. In particular, a framework for the definition and realization of the closed-loop electromyographic control of these devices has been presented and implemented. The results were quite promising, putting in evidence that, in the future, there could be two different approaches for the realization of artificial devices. On one side there could be the EMG-controlled hands, with compliant fingers but only one active degree of freedom. On the other side, more performing artificial hands could be directly interfaced with the peripheral nervous system, thus establishing a bi-directional communication with the human brain