Multimodal theory has developed out of social semiotics and can be seen as a response to the rise in the use of new technologies for the creation, distribution and consumption of media texts and the need to find new ways of describing and explaining their role in representation and communication. Its development is historical. It is a response to change over time. The incorporation of the visual into social semiotics marks a key moment in the development of multimodal theory. Visual literacy is discussed in relation to changes in modes of representation and a critique of this concept is provided. This is conducted in relation to how the visual modality has been integrated into social semiotics as a platform for research into multimodal communication more generally. Framing is developed along three main lines of enquiry (semiotic, cognitive and affective) as alternative ways of accounting for some of these shifts in communication and each are presented in the form of case studies. Framing and its close relationship with composition in media texts is discussed and this understanding, one that emphasise proximity as a multimodal principle, is applied to the visual design of content, the realisation of context through the provision visual cues, and later to embodiment and urban space. The three case studies, the application of framing to a range of media texts, the critical judgements made about the role visual in contemporary theory and the application of these concepts to multimodality are presented as part of an intellectual journey.

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Automatic detection of space objects in optical images is important to close proximity operations, relative navigation, and situational awareness. To better protect space assets, it is very important not only to know where a space object is, but also what the object is. In this dissertation, a method for detecting multiple 1U, 2U, 3U, and 6U CubeSats based on the faster region-based convolutional neural network (Faster R-CNN) is described. CubeSats detection models are developed using Web-searched and computer-aided design images. In addition, a two-step method is presented for detecting a rotating CubeSat in close proximity from a sequence of images without the use of intrinsic or external camera parameters. First, a Faster R-CNN trained on synthetic images of 1U, 2U, 3U, and 6U CubeSats locates the CubeSat in each image and assigns a weight to each CubeSat class. Then, these classification results are combined using Dempster's rule. The method is tested on simulated scenarios where the rotating 3U and 6U CubeSats are in unfavorable views or in dark environments. Faster R-CNN detection results contain useful information for tracking, navigation, pose estimation, and simultaneous localization and mapping. A coarse single-point attitude estimation method is proposed utilizing the centroids of the bounding boxes surrounding the CubeSats in the image. The centroids define the line-of-sight (LOS) vectors to the detected CubeSats in the camera frame, and the LOS vectors in the reference frame are assumed to be obtained from global positioning system (GPS). The three-axis attitude is determined from the vector observations by solving Wahba's problem. The attitude estimation concept is tested on simulated scenarios using Autodesk Maya.

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Despite the abundance of past research that has been conducted on various antecedents leading to promotability - "the favorability of an employee's advancement prospects" (Greenhaus, Parasuraman & Wormley, 1990), there is a paucity of research on the role that work proximity plays in determining an employee’s promotion into leadership positions. This research study looks to understand what role work proximity plays in the ability for a subordinate to be promoted into a leadership role. Leader member Exchange Theory and Signaling Theory all point to trust, perceived similarity and upward impression management as the antecedents having the most effect on the subordinate’s ability to be promoted into a leadership role when they do not physically work from the same location as their manager. The first phase of this research study aims to validate and refine those antecedents in a single case study using a qualitative and exploratory approach. As a result of the pilot study, trust was moved to control variable, informal interaction was added as a new antecedent and work proximity was changed from a moderating variable to a main effect variable. Additionally, perceived similarity and perceived positive impression were also identified as possible mediating variables. The results of this research study have shown that the extent to which a manger can physically “see” or “notice” their subordinate regardless of their physical work location, being co-located or not, is related to the manager’s assessment of the subordinates promotability. This finding answers the research question: What role does work proximity to one’s manager play in employees being promoted into leadership roles? / Business Administration/Human Resource Management

Spacecraft relative motion modeling and control promises to enable or augment a wide range of missions for scientific research, military applications, and space situational awareness. This dissertation focuses on the development of novel, optimization-based, control design for some representative relative-motion-enabled missions. Spacecraft relative motion refers to two (or more) satellites in nearly identical orbits. We examine control design for relative configurations on the scale of meters (for the purposes of proximity operations) as well as on the scale of tens of kilometers (representative of science gathering missions). Realistic control design for satellites is limited by accurate modeling of the relative orbital perturbations as well as the highly constrained nature of most space systems. We present solutions to several types of optimal orbital maneuvers using a variety of different, realistic assumptions based on the maneuver objectives. Initially, we assume a perfectly circular orbit with a perfectly spherical Earth and analytically solve the under-actuated, minimum-energy, optimal transfer using techniques from optimal control and linear operator theory. The resulting open-loop control law is guaranteed to be a global optimum. Then, recognizing that very few, if any, orbits are truly circular, the optimal transfer problem is generalized to the elliptical linear and nonlinear systems which describe the relative motion. Solution of the minimum energy transfer for both the linear and nonlinear systems reveals that the resulting trajectories are nearly identical, implying that the nonlinearity has little effect on the relative motion. A continuous-time, nonlinear, sliding mode controller which tracks the linear trajectory in the presence of a higher fidelity orbit model shows that the closed-loop system is both asymptotically stable and robust to disturbances and un-modeled dynamics. Next, a novel method of computing discrete-time, multi-revolution, finite-thrust, fuel-optimal, relative orbit transfers near an elliptical, perturbed orbit is presented. The optimal control problem is based on the classical, continuous-time, fuel-optimization problem from calculus of variations, and we present the discrete-time analogue of this problem using a transcription-based method. The resulting linear program guarantees a global optimum in terms of fuel consumption, and we validate the results using classical impulsive orbit transfer theory. The new method is shown to converge to classical impulsive orbit transfer theory in the limit that the duration of the zero-order hold discretization approaches zero and the time horizon extends to infinity. Then the fuel/time optimal control problem is solved using a hybrid approach which uses a linear program to solve the fuel optimization, and a genetic algorithm to find the minimizing time-of-flight. The method developed in this work allows mission planners to determine the feasibility for realistic spacecraft and motion models. Proximity operations for robotic inspection have the potential to aid manned and unmanned systems in space situational awareness and contingency planning in the event of emergency. A potential limiting factor is the large number of constraints imposed on the inspector vehicle due to collision avoidance constraints and limited power and computational resources. We examine this problem and present a solution to the coupled orbit and attitude control problem using model predictive control. This control technique allows state and control constraints to be encoded as a mathematical program which is solved on-line. We present a new thruster constraint which models the minimum-impulse bit as a semi-continuous variable, resulting in a mixed-integer program. The new model, while computationally more expensive, is shown to be more fuel-efficient than a sub-optimal approximation. The result is a fuel efficient, trajectory tracking, model predictive controller with a linear-quadratic attitude regulator which tracks along a pre-computed ``safe'' trajectory in the presence of un-modeled dynamics on a higher fidelity orbital and attitude model. / Ph. D.

Worldwide, many wildlife populations are in decline or facing extinctions due to overhunting, habitat loss and fragmentation, infrastructure development, resource extraction, and climate change. These threats are particularly detrimental to Madagascar's most iconic wildlife - lemurs (Primates: Lemuridae) – which have been declared Earth's most threatened mammal group, with 103 of 107 species currently threatened with extinction. Due to the numerous anthropogenic pressures facing lemurs, concerted efforts have been made to design and implement effective conservation management plans as well as to maintain captive populations. My dissertation focused on understanding the behavior and physiology of two critically endangered lemur species: the golden crowned sifaka (Propithecus tattersalli) and the Coquerel's sifaka (P. coquereli). To gain a better understanding of free-living golden-crowned sifaka habitat requirements, I combined behavior data with Dynamic Brownian Bridge Movement Models and Resource Selection Functions to examine the influence of abiotic, biotic, and anthropogenic factors on movement and foraging patterns. I found that movement rates and core area use were greater in the rainy season than in the dry season. My findings also indicated that roads and human villages influenced the locations where sifakas choose to forage, demonstrating the need to strategically place infrastructure to limit wildlife disturbance (Chapter 2). Second, having explored potential stressors in wild sifaka, I wanted to explore relationships between physiological stress and captive care in sifakas. Specifically, I investigated relationships between captive sifaka fecal glucocorticoid metabolite levels and captive husbandry conditions. I found that age and contraceptive use, but not enclosure type, season, or sex, influenced glucocorticoid excretion (Chapter 3). These results highlight the importance of assessing the physiological impacts of captive husbandry conditions to ensure that the best animal welfare practices can be maintained. Third, to combat challenges in studying animal behavior using observational approaches, I designed and constructed low-cost, open-source proximity loggers to remotely examine fine-scale movement and social behaviors in wild and captive sifakas. I found a relationship between radio signal strength and distance between tracking devices (R2 = 0.8812), demonstrating that proximity sensors can effectively collect data on close range group-level behavior (Chapter 4). These modular devices can be used on an array of wildlife species to explore social interactions that require high resolution spatial data. Taken together, these results illustrate the opportunity of connecting behavioral, ecological, physiological, and technological approaches to gain critical insight into the multidimensional nature of wildlife conservation. Lastly, I discussed future steps that can be taken to extend the framework established by my dissertation research to address the complex dynamics shaping conservation in Madagascar (Chapter 5). / Doctor of Philosophy / Worldwide, many wildlife populations are at risk of extinction due to hunting, habitat loss, infrastructure development, and climate change. These threats are particularly detrimental to lemurs – a diverse group of primates found only on the island of Madagascar. Due to the numerous pressures facing lemurs, efforts have been made to design and implement effective conservation management plans and maintain captive populations. My dissertation focused on understanding the behavior and physiology of two critically endangered lemur species: the golden crowned sifaka (Propithecus tattersalli) and the Coquerel's sifaka (P. coquereli). To better understand wild golden-crowned sifaka habitat needs, I followed six groups of sifakas in humid, moderate, and dry forests to examine the influence of season, forest type, and human development on their movement patterns and feeding locations. I found that sifakas moved more and used more space in the rainy season than in the dry season. Several sifaka groups also avoided feeding near roads and human villages, demonstrating the need to strategically place infrastructure to limit negative effects on wildlife (Chapter 2). Second, having explored potential stressors in wild sifaka, I wanted to explore relationships between physiological stress and captive care in sifakas. Specifically, I analyzed sifaka fecal samples to investigate relationships between captive sifaka husbandry conditions and physiological stress (i.e., glucocorticoid levels). I found that age and birth control use, but not enclosure type, season, or sex, influenced glucocorticoid levels (Chapter 3). These results highlight the importance of assessing the physiological impacts of captive husbandry conditions to ensure that the best animal welfare practices can be maintained. Third, to combat challenges in studying animal behavior using observational approaches, I designed and constructed low-cost, open-source tracking devices to remotely study fine-scale movement and social behaviors in wild and captive sifakas. I found that the distance between tracking devices can be determined by using proximity sensing radio chips. This demonstrated that proximity sensors can effectively collect data on close range group-level behavior (Chapter 4). These modular devices can be used on an array of wildlife species to explore social interactions that require high resolution spatial data. Taken together, these results illustrate the benefits of using behavioral, physiological, and technological approaches to gain insight into the multidimensional nature of wildlife conservation. Lastly, I discussed future steps that can be taken to extend the framework established by my dissertation research to address the complex dynamics shaping conservation in Madagascar (Chapter 5).

Programmatically, the aim of the thesis is to create a new place to commemorate the lives lost in the Guatemalan Civil War in the town of Xix (pronounced â sheeshâ ), Guatemala. Currently, Xixâ s boarding school is the only place that houses a memorial for those 113 lives lost in Xix during the war. The existing memorial pavilion that houses a statue and commemorative plaque are being weathered by the elements. It is only a matter of time before the statue and plaque are overcome by the elements. This situation resulted in a complete transformation in the way that Xix remembers the war. This thesis project reroutes the communityâ s Memorial Day parade so that the procession ends at the proposed memorial plaza. Parade goers travel through the town of Xix to the boarding school where the new memorial is. The new memorial consist of a bridge that leads to a room that houses the existing statue and plaque, and the room has a balcony that overlooks a plaza that includes a small green amphitheater and memorial fountain. The circle and the square became the generating forms for this place, and through an exploration of nineteen relationships that could be shared among the circle and the square two were found dominate in regulating many possible relationships. Proximity was the first of the two dominate relationships and the second is proportion. The exploration is set in two stages: research (Circling the Square: Proximity and Proportions), and demonstration of the dominate relationships (Site: Circular Proximity, Elevations + Sections: Boundary of Proportions, and Squaring the Circle). / Master of Architecture

This thesis presents results of an experimental investigation to characterize single straight steel fiber pullout in Ultra-High Performance Concrete (UHPC). Several parameters were explored including the distance of fibers to the edge of specimen, distance between fibers, and fiber volume in the matrix. The pullout load versus slip curve was recorded, from which the pullout work and maximum pullout load for each series of parameters were obtained. The curves were fitted to an existing fiber pullout model considering bond-fracture energy, Gd, bond frictional stress, 𝛕0, and slip hardening-softening coefficient, 𝜷. The representative load-slip curve characterizing the fiber pullout behavior will be implemented into a computational modeling protocol, for concrete structures, based on Lattice Discrete Particle Modeling (LDPM). The parametric study showed that distances over 12.7 mm from the edge of the specimen have no significant effect on the maximum pullout load and work. Edge distances of 3.2 mm decreased the average pullout work by 26% and the maximum pullout load by 24% for mixes with 0% fiber volume. The distance between fibers did not have a significant effect on the pullout behavior within this study. Slight differences in pullout behavior between the 2% and 4% fiber volumes were observed including slight increase in the maximum pullout load when increasing fiber volume. The suggested fitted parameters for modeling with 2% and 4% fiber volumes are a bond-fracture energy value of zero, a bond friction coefficient of 2.6 N/mm² and 2.9 N/mm² and a slip-hardening coefficient of 0.21 and 0.18 respectively. / Master of Science

Due to inadequate training and an undeveloped ability to recognize dangerous scenarios, youth workers are exposed to many dangers in the agriculture and lawn care industries. With the abundance of new technologies available on the market, a project was devised to prevent youth from heat exhaustion and equipment run overs by employing sensor based technologies. Using aural temperature measurement techniques involving a thermistor and thermopile, an accurate estimation of core body temperature can be made. The measurements performed by the devices are recorded and transmitted wirelessly over a ZigBee network using XBee radiofrequency modules. Utilizing the properties of radiofrequency transmission, the Received Signal Strength Indication (RSSI) is used to approximate the distance between devices. With accuracy comparable to GPS methods and no necessity for line of sight to sky, RSSI supplies a more than adequate estimate for proximity distance. The temperature and RSSI values are then sent to a coordinating modem where the data is displayed for the supervisor. After testing and calibrating the device, it was found that these methods are effective for the monitoring of core body temperature and proximity of workers. The temperature sensor was able to measure temperatures with less than 0.25% error and the proximity sensor was able to estimate distance within 1.25 meters at close range. / Master of Science