Thesis (Honors)--University of South Florida, 2008. / Title from cover. "April 24, 2008." Includes bibliographical references (p. 41).

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Patrick Hollis, Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed June 18, 2004). Includes bibliographical references.

Thesis (Ph.D.) -- University of Texas at Arlington, 2008.

The range camera in Microsoft's Kinect, intended for the Xbox 360 gaming console, offers a powerful alternative to the many standard sensors used in robotics for gathering spatial information about a robot’s surroundings. The recently-released Kinect is the first commercially available product to provide depth data of its resolution and accuracy with a price tag within reach of many robotics projects. The work described in this paper explores the feasibility of using this sensor by developing a robot that relies solely on the Kinect for sensory data. This robot successfully performs standard navigational procedures, demonstrating the possibility of integrating spatial information from the Kinect into a real-time robotics application. This paper documents the techniques used to integrate the Kinect into the system, highlighting the key benefits and limitations of the sensor. / text

Autonomous vehicles (AVs) may soon be publicly available and are expected to increase both network capacity and travel demand. Reduced safety margins from computer precision may increase network capacity and allow for more efficient intersection controls. AVs also offer the option of repositioning trips to avoid parking fees or share the vehicle between household members, which may increase the total number of vehicle trips and decrease the relative utility of transit. Since AVs may be available within one or two decades, which is within the span of long-term planning models, practitioners may soon wish to predict the effects of AVs on traffic networks. This thesis modifies the four-step planning model commonly used by practitioners to include AV behaviors and capacity improvements. Because dynamic traffic assignment (DTA) offers more realistic flow propagation and intersection control options, the four-step model is modified to incorporate DTA with endogenous departure time choices. To facilitate modeling of AV intersections, the tile-based reservation (TBR) control policy is simplified into a conflict region (CR) model compatible with general simulation-based DTA and with greatly improved computational tractability. Results suggest that although the total number of personal-vehicle trips may almost double (due to repositioning trips to the origin to avoid parking costs), increases in network and intersection capacity can mostly offset or even improve network conditions. Use of dynamic flow propagation instead of static travel time functions in the four-step model results in predictions of increased average travel speed although both static and dynamic planning models predict a high reliance on repositioning trips (i.e., empty-vehicle travel). To study AV behaviors in DTA, this thesis first integrates DTA into the four-step model with the addition of departure time choice. This model alone may be useful for practitioners as departure time modeling is a major concern with DTA planning models. Also, the TBR intersection policy has only been studied in micro-simulation with heuristic routing strategies. The CR model opens this new technique to study under UE behavior, which is the first step for the bridge between technology demonstration simulations to models practitioners can use to evaluate implementation. . Therefore, the models developed here for the purposes of predicting AV trip and mode choices may themselves become useful tools for other applications. / text

No description available.

Apomixis is an intriguing and agronomically valuable asexual reproductive pathway resulting in seeds that give rise to plants that are identical in genotype to the female parent. Apomixis is absent in agriculturally important seed crops and our work has focused on the analysis of apomixis in the daisy-like genus Hieracium which contains sexual and apomictic species. Prior studies have shown that apomixis in Hieracium is controlled by two dominant loci. The LOA controls the avoidance of meiosis during female gametophyte (embryo sac) formation and the LOP locus is required for fertilization independent embryo formation during seed initiation. The genes conferring apomixis are unknown. In this study we focused on the events of autonomous seed initiation. Cytological examination of apomictic mutants that have lost LOA or LOP and analysis of their progeny enabled us to characterize developmental aspects associated with the function of these loci. Upon removal of LOA meiosis occurs normally and LOP segregates with a 1:1 ratio in the progeny, characterizing maternal gametophytic control. We also show that autonomous embryo formation segregates with autonomous endosperm formation, suggesting that these two loci are closely linked. However, upon meiotic division, embryo lethal components arise and embryo development in apomeiosis mutants was generally defective and seed set was low. Similarly, upon removal of LOP, apomixis initiation occurs normally and unreduced embryo sacs can only form seeds if pollinated. Autonomous seed initiation is actively repressed in the sexual model plant Arabidopsis by the action of a chromatin remodelling complex encoded by the FERTILIZATION INDEPENDENT SEED (FIS)-class genes. These genes are homologues of the Drosophila PcG complex that also repress gene expression throughout Drosophila development. Mutations in the FIS-class genes lead to elements of apomixis, such as autonomous endosperm, and in one particular mutant, autonomous egg cell development. Given the similarity in apomictic and FISclass gene mutant phenotype we isolated three homologues from sexual and apomictic Hieracium plants: FERTILIZATION INDEPENDENT ENDOSPERM (FIE), MULTICOPY SUPPRESSOR OF IRA1 (MSI1) AND RETINOBLASTOMA (RBR). FIS-class genes from sexual and apomicit Hieracium and examined their expression, interaction and function during seed initiation. The isolated Hieracium FIS-class genes were highly conserved in sexual and apomictic plants in terms of gene sequence and temporal and spatial expression pattern. Analysis of protein interactions by yeast-two hybrid showed that the HFIE gene from sexual and apomictic plants does not interact with other complex members in the same manner found in Arabidopsis. Protein modelling uncovered structural differences between the Arabidopsis and Hieracium FIE proteins. RNAi- mediated down-regulation of HFIE in sexual Hieracium did not lead to autonomous seed initiation indicating HFIE was not part of a repressive complex. Down-regulation of HFIE in sexual and apomictic plants revealed the gene was essential for embryo growth and viability. Therefore, FIS-complex genes interact differently in Arabidopsis and Hieracium and have different developmental roles. In summary, the results presented here suggest that the FIS-genes are not mutated in apomictic Hieracium plants, but they interact differently relative to the Arabidopsis counterparts and play a fundamental role in embryogenesis. Thus, engineering autonomous seed into crops will not depend on mutating these genes but rather in uncovering the molecular signal that triggers apomictic development. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1337073 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2008

Highly automated driving systems promise increased road traffic safety, as well as positive impacts on sustainable transportation by means of increased traffic efficiency and environmental friendliness. The design and development of such systems require scientific advances in a number of areas. One area is the vehicle's electrical/electronic (E/E) architecture. The E/E architecture can be presented using a number of views, of which an important one is the functional view. The functional view describes the decomposition of the system into its main logical components, along with the hierarchical structure, the component inter-connections, and requirements. When this view captures the principal ideas and patterns that constitute the foundation of a variety of specific architectures, it may be termed as a reference architecture. Two reference architectures for highly automated driving form the principal contribution of this thesis. The first reference architecture is for cooperative driving. In a cooperative driving situation, vehicles and road infrastructure in the vicinity of a vehicle continuously exchange wireless information and this information is then used to control the motion of the vehicle. The second reference architecture is for autonomous driving, wherein the vehicle is capable of driver-less operation even without direct communication with external entities. The description of both reference architectures includes their main components and the rationale for how these components should be distributed across the architecture and its layers. These architectures have been validated via multiple real-world instantiations, and the guidelines for instantiation also form part of the architecture description. A comparison with similar architectures is also provided, in order to highlight the similarities and differences. The comparisons show that in the context of automated driving, the explicit recognition of components for semantic understanding, world modeling, and vehicle platform abstraction are unique to the proposed architecture. These components are not unusual in architectures within the Artificial Intelligence/robotics domains; the proposed architecture shows how they can be applied within the automotive domain. A secondary contribution of this thesis is a description of a lightweight, four step approach for model based systems engineering of highly automated driving systems, along with supporting model classes. The model classes cover the concept of operations, logical architecture, application software components, and the implementation platforms. The thesis also provides an overview of current implementation technologies for cognitive driving intelligence and vehicle platform control, and recommends a specific setup for development and accelerated testing of highly automated driving systems, that includes model- and hardware-in-the-loop techniques in conjunction with a publish/subscribe bus. Beyond the more "traditional" engineering concepts, the thesis also investigates the domain of machine consciousness and computational self-awareness. The exploration indicates that current engineering methods are likely to hit a complexity ceiling, breaking through which may require advances in how safety-critical systems can self-organize, construct, and evaluate internal models to reflect their perception of the world. Finally, the thesis also presents a functional architecture for the brake system of an autonomous truck. This architecture proposes a reconfiguration of the existing brake systems of the truck in a way that provides dynamic, diversified redundancy, and an increase in the system reliability and availability, while meeting safety requirements. / <p>QC 20151216</p>

An autonomous system has been widely applied for various civil/military research because of its versatile capability of understanding high-level intent and direction of a surrounding environment and targets of interest. However, as autonomous systems can be out of control to cause serious loss, injury, or death in the worst case, the verification of their functionalities has got increasing attention. For that reason, this study is focused on the verification of a heterogeneous multi-agent autonomous system. The thesis first presents an overview of formal methods, especially focuses on model checking for autonomous systems verification. Then, six case studies are presented to verify the decision making behaviours of multi-agent system using two basic scenarios: surveillance and convoy. The initial system considered in the surveillance mission consists of a ground control system and a micro aerial vehicle. Their decision-making behaviours are represented by means of Kripke model and computational tree logic is used to specify the properties of this system. For automatic verification, MCMAS (Model Checker for Multi-Agent Systems) is adopted due to its novel capability to accommodate the multi-agent system. After that, the initial system is extended to include a substitute micro aerial vehicle. These initial case studies are then further extended based on SEAS DTC exemplar 2 dealing with behaviours of convoy protection. This case study includes now a ground control system, an unmanned aerial vehicle, and an unmanned ground vehicle. The MCMAS successfully verifies the targeting behaviours of the team-level unmanned systems. Reversely, these verification results help retrospectively improve the design of decision-making algorithms by considering additional agents and behaviours during four steps of scenario modification. Consequently, the last scenario deals with the system composed of a ground control system, two unmanned aerial vehicles, and four unmanned ground vehicles with fault-tolerant and communications relay capabilities. In conclusion, this study demonstrates the feasibility of model checking algorithms as a verification tool of a multi-agent system in an initial design stage. Moreover, this research can be an important first step of the certification of multi-agent autonomous systems for the domains of robotics, aerospace and aeronautics.

In this thesis, we investigate the orbit control strategies of small satellites in Low Earth Orbits (LEO) where the disturbance effects are significant, in particular the nonspherical Earth and atmospheric drag effects. These orbits are not suitable to be controlled by using traditional ground-based control strategies which generally require high-thrust propulsion systems and other expensive resources, both onboard and in the ground segment. In order to react to those disturbances spontaneously and keep a small satellite at a pre-defined station using its limited resources, autonomous orbit control technology needs to be enabled. With the current advances in navigation and propulsion technology, as well as onboard computation systems, the only key issue that needs further investigations for practical implementation of an autonomous orbit operation system is the control algorithm. The orbit control strategies we investigate here are treated separately for each of the orbital control phases, i.e. orbit deployment and acquisition, orbit transfer and orbit maintenance. We present various forms of the solutions of the epicycle motion which allow us to treat each control problem according to the control requirements, nature of perturbations, control time scales and available resources. Although applied in different manners, the optimal low-thrust control scheme is a common aim for all control problems investigated here, as we mainly focus upon applications for low cost small satellites in LEO. The verifications of the strategies proposed in this thesis have been demonstrated not only via computer simulations, but also successfully demonstrated on in-orbit small satellite platforms thanks to an active small satellite programme at Surrey Space Centre. The success of this study is hoped to provide a valuable basis for satellite orbit operations which will involve larger number of satellites with more complex configurations in the future.