Fly with me : algorithms and methods for influencing a flock

As robots become more affordable, they will begin to exist in the world in greater quantities. Some of these robots will likely be designed to act as components in specific teams. These teams could work on tasks that are too large or complex for a single robot - or that are merely more efficiently accomplished by a team - such as surveillance in a large building or product delivery to packers in a warehouse. Multiagent systems research studies how these teams are formed and how they work together. Ad hoc teamwork, a newer area of multiagent systems research, studies how new robots can join these pre-existing teams and assist the team in accomplishing its goal. This dissertation extends and applies research in ad hoc teamwork towards the general area of flocking, which is an emergent swarm behavior. In particular, the work in this dissertation considers how ad hoc agents - called influencing agents in this dissertation - can join a flock, be recognized by the rest of the flock as part of the flock, influence the flock towards particular behaviors through their own behavior, and then separate from the flock. Specifically, the primary research question addressed in this dissertation is How can influencing agents be utilized in various types of flocks to influence the flock towards a particular behavior? In order to address this research question, this dissertation makes six main types of contributions. First, this dissertation formalizes the problem of using influencing agents to influence a flock. Second, this dissertation contributes and analyzes algorithms for influencing a flock to a desired orientation. Third, this dissertation presents methods for determining how to best add influencing agents to a flock. Fourth, this dissertation provides methods by which influencing agents can join and then leave a flock in motion. Fifth, this dissertation evaluates some of the influencing agent algorithms on a robot platform. Sixth, although the majority of this dissertation assumes the influencing agents will join a flock that behaves similarly to European starlings, this dissertation also provides insight into when and how its algorithms are generalizable to other types of flocks as well as to general teamwork and coordination research. All of the methods presented in this dissertation are empirically evaluated using a simulator that can support large flocks.Computer Science

Animating Predator and Prey Fish Interactions

Schooling behavior is one of the most salient social and group activities among fish. They form schools for social reasons like foraging, mating and escaping from predators. Animating a school of fish is difficult because they are large in number, often swim in distinctive patterns that is they take the shape of long thin lines, squares, ovals or amoeboid and exhibit complex coordinated patterns especially when they are attacked by a predator. Previous work in computer graphics has not provided satisfactory models to simulate the many distinctive interactions between a school of prey fish and their predator, how does a predator pick its target? and how does a school of fish react to such attacks? This dissertation presents a method to simulate interactions between prey fish and predator fish in the 3D world based on the biological research findings. Firstly, a model is described by representing a school of fish as a complex network information flow with structural properties. Using this model, a predator fish targeting isolated peripheral fish is simulated. Secondly, the escape behavior state machine model and escape maneuvers exhibited by fish schools are described. The escape maneuvers include compact, avoid, fast avoid, skitter, fountain, flash, ball, split, join, herd, vacuole, and hourglass are identified in the biological studies. This proposed escape behavior animation model can free an animator from dealing with the low-level animations but instead, control the fish behavior on a higher level by modifying a state machine and a small set of system parameters. With the state machine and relatively few system parameters, the proposed system is stable, predictable, and easy to tune, which represent important properties for animators to control the outcome. This system is developed in Unity (3D). In addition, a plug-in is also developed for full-fledged graphics tool Blender software to simulate escape maneuvers. The animator has to simply select escape maneuvers, adjust parameters and work on animating predator using keyframe method. It does not deal with the state machine model. The proposed model is useful not only in generating group behaviors but also in scientific visualization tool for studying fish behavior

Social decision-making driven by artistic explore-exploit tension

We studied social decision-making in the rule-based improvisational dance $There$ $Might$ $Be$ $Others$, where dancers make in-the-moment compositional choices. Rehearsals provided a natural test-bed with communication restricted to non-verbal cues. We observed a key artistic explore-exploit tension in which the dancers switched between exploitation of existing artistic opportunities and riskier exploration of new ones. We investigated how the rules influenced the dynamics using rehearsals together with a model generalized from evolutionary dynamics. We tuned the rules to heighten the tension and modeled nonlinear fitness and feedback dynamics for mutation rate to capture the observed temporal phasing of the dancers' exploration-versus-exploitation. Using bifurcation analysis, we identified key controls of the tension and showed how they could shape the decision-making dynamics of the model much like turning a "dial" in the instructions to the dancers could shape the dance. The investigation became an integral part of the development of the dance

Developing a Healthy Work Environment for Radiology Nurses Through Metaphor

A healthy work environment is an essential part of a nurse\u27s professional practice. Providing nurses access to resources to understand the importance of a healthy work environment should be present in healthcare organizations. After evaluating a Radiology Department at a large hospital in the Midwest, the themes of communication, collaboration, and authentic leadership were revealed as areas to be improved upon for this work environment. Not only will these themes contribute to the workplace as well as providing effective patient care. The American Association of Critical-Care Nurses (AACN) Standards for Establishing and Sustaining Healthy Work Environments (Barden, 2005:2016) and Martha Rogers\u27 (1970) Theory of Unitary Human Beings guided this project to create a culture change in a Radiology Department aimed at fostering a healthy work environment. This project will be guided by a metaphor demonstrating the importance of a healthy work environment; the metaphor uses geese flying together to represent a healthy work environment as there are many lessons that can be learned from geese. Finally, there is a thorough exploration in how nursing leadership can support a healthy work environment

Multi-Scale Mathematical Modeling of Prion Aggregate Dynamics and Phenotypes in Yeast Colonies

Prion diseases are a multi-scale biological phenomenon that requires understanding intracellular processes as well as how cells interact with each other and their environment. In mammals, prion diseases are progressive, untreatable, and fatal. Yeast prion phenotypes are harmless and reversible, which suggests a deep understanding of the reversal of prion phenotypes in yeast may be informative to mammalian diseases. In yeast, the loss of some prion phenotypes appears to be stochastic and spatially dependent, suggesting a cell-based model of yeast prion dynamics would be a powerful tool for comparisons with experimental results and hypothesis generation. In this work, we consider the components necessary to develop such a model that depicts both the biochemical-, intracellular-, and colony-level scales in yeast prion phenotypes. We first review the literature of mathematical models of the intracellular processes of prion disease. We then review common approaches to cell-based modeling of multicellular systems and how they have led to biological insights in other systems. This chapter ends with a discussion of future studies aimed at motivating how these two types of models can be coupled to produce multi-scale models of prion phenotypes

Exercising Obedience: John Cassian and the Creation of Early Monastic Subjectivity

John Cassian (360-435 CE) started his monastic career in Bethlehem. He later traveled to the Egyptian desert, living there as a monk, meeting the venerated Desert Fathers, and learning from them for about fifteen years. Much later, he would go to the region of Gaul to help establish a monastery there by writing monastic manuals, the Institutes and the Conferences. These seminal writings represent the first known attempt to bring the idealized monastic traditions from Egypt, long understood to be the cradle of monasticism, to the West. In his Institutes, Cassian comments that a monk ought by all means to flee from women and bishops (Inst. 11.18). This is indeed an odd comment from a monk, apparently casting bishops as adversaries rather than models for the Christian life. In this paper, therefore, I argue that Cassian, in both the Institutes and the Conferences, is advocating for a distinct separation between monastics and the institutional Church. In Cassian\u27s writings and the larger corpus of monastic writings from his era, monks never referred to early Church fathers such as Irenaeus or Tertullian as authorities; instead they cited quotes and stories exclusively from earlier, venerated monks. In that sense, monastic discourse such as Cassian\u27s formed a closed discursive system, consciously excluding the hierarchical institutional Church. Furthermore, Cassian argues for a separate monastic authority based not on apostolic succession but rather on what I term apostolic praxis, the notion that monastic practices such as prayer and asceticism can be traced back to the primitive church. I supplement my study of Cassian\u27s writings with Michel Foucault\u27s analysis of the creation of subjects in order to examine what I believe to be Cassian\u27s formation of a specifically Egyptian form of monastic subjectivity for his audience, the monks of Gaul. In addition, I employ Foucault\u27s concepts of disciplinary power and pastoral power to demonstrate the effect Cassian\u27s rhetoric would have upon his direct audience, as well as many other monks throughout history