Exploring Topological Environments

Simultaneous localization and mapping (SLAM) addresses the task of incrementally building a map of the environment with a robot while simultaneously localizing the robot relative to that map. SLAM is generally regarded as one of the most important problems in the pursuit of building truly autonomous mobile robots. This thesis considers the SLAM problem within a topological framework, in which the world and its representation are modelled as a graph. A topological framework provides a useful model within which to explore fundamental limits to exploration and mapping. Given a topological world, it is not, in general, possible to map the world deterministically without resorting to some type of marking aids. Early work demonstrated that a single movable marker was sufficient but is this necessary? This thesis shows that deterministic mapping is possible if both explicit place and back-link information exist in one vertex. Such 'directional lighthouse' information can be established in a number of ways including through the addition of a simple directional immovable marker to the environment. This thesis also explores non-deterministic approaches that map the world with less marking information. The algorithms are evaluated through performance analysis and experimental validation. Furthermore, the basic sensing and locomotion assumptions that underlie these algorithms are evaluated using a differential drive robot and an autonomous visual sensor

Exploring Topological Environments

Simultaneous localization and mapping (SLAM) addresses the task of incrementally building a map of the environment with a robot while simultaneously localizing the robot relative to that map. SLAM is generally regarded as one of the most important problems in the pursuit of building truly autonomous mobile robots. This thesis considers the SLAM problem within a topological framework, in which the world and its representation are modelled as a graph. A topological framework provides a useful model within which to explore fundamental limits to exploration and mapping. Given a topological world, it is not, in general, possible to map the world deterministically without resorting to some type of marking aids. Early work demonstrated that a single movable marker was sufficient but is this necessary? This thesis shows that deterministic mapping is possible if both explicit place and back-link information exist in one vertex. Such 'directional lighthouse' information can be established in a number of ways including through the addition of a simple directional immovable marker to the environment. This thesis also explores non-deterministic approaches that map the world with less marking information. The algorithms are evaluated through performance analysis and experimental validation. Furthermore, the basic sensing and locomotion assumptions that underlie these algorithms are evaluated using a differential drive robot and an autonomous visual sensor

Dancing 'Nessun Dorma'

In the 1990s and into the beginning of the 21st century, Luciano Pavarotti helped popularise opera through singing the anthem for the Italia90 soccer World Cup; through concerts with the Three Tenors, and through his inter-music-genre charity concerts, Pavarotti and Friends. In doing so, he helped bring opera, and in particular ‘Nessun Dorma’ from Puccini’s opera Turandot, to a wider audience than ever before. In Daniel Somerville’s practice-research performed presentation, which draws on his research into operatic movement, he muses on how along with positioning ‘Nessun Dorma’ as the most recognisable tune in opera, Pavarotti also instilled an idea of how opera singers move that affirms negative stereotypes of the arm-raising, hand-waving, ‘stand and deliver’ opera star, while also divorcing the aria from its original context. Dancing ‘Nessun Dorma’ seeks to restore the aria to its original literary context and to reclaim the narrative of Turandot through presenting the moving body alongside operatic and autobiographical anecdote. Movement practice participating in, and allowing, a reassessment and revisiting of an aria and narrative that sits problematically at the intersection of Orientalist fantasy and Italian pride

Developing Unique Engineering Solutions to Improve Patient Safety

Many efforts to improve healthcare safety have focused on redesigning processes of care or retraining clinicians. Far less attention has been focused on the use of new technologies to improve safety. We present the results of a unique collaboration between the VA National Center for Patient Safety (NCPS) and the Thayer School of Engineering at Dartmouth College. Each year, the NCPS identifies safety problems across the VA that could be addressed with newly-engineered devices. Teams of Thayer students and faculty participating in a senior design course evaluate and engineer a solution for one of the problems. Exemplar projects have targeted surgical sponge retention, nosocomial infections, surgical site localization, and remote monitoring of hospitalized patients undergoing diagnostic testing and procedures. The program has served as an avenue for engineering students and health care workers to solve problems together. The success of this academic-clinical partnership could be replicated in other settings

Studies in Neoproterozoic Paleontology

The Neoproterozoic Era was one of major biotic change against a background marked by fluctuations in oceanic and atmospheric chemistry, formation and rifting of the supercontinent Rodinia, and at least two global glaciations (Snowball Earth events). Presented here are three studies of differing aspects of those biological changes. The first is a systematic study of the diverse and well-preserved, organic-walled microfossil assemblage of the Alinya Formation of eastern Officer Basin, Australia. The use of scanning electron microscopy (SEM) revealed an unexpected level of morphological detail not visible in transmitted light microscopy and led to the recognition of new species and emendation of existing species as well as establishment of degradational sequences. In total, thirty-three taxa are described here including nineteen previously named forms, five newly described species and two new combinations. The second study describes the organic-walled microfossil assemblages from five successions that span the first (Sturtian) glaciation (~717 Ma) and interglacial interval (>635 Ma), and integrates those data with a critical evaluation of primary paleontological literature of units deposited from ~850 to 650 Ma. The described successions from Australia and Svalbard record low species richness throughout this interval and when placed in context of all available body fossil data from the mid-Neoproterozoic, indicate global species richness may have decreased much earlier than previously realized. This finding of temporal decoupling between loss of richness and glacial onset suggests the extinctions previously associated with the Snowball Earth glacial events may not have been glacially driven. The last of these three studies provides a broader view of the early to middle Neoproterozoic biosphere (1 Ga to 635 Ma) and describes application of the CONOP correlation and seriation algorithm to a new database of paleontological, geochemical and radiometric data. Paleobiological (first and last species appearances), geochemical and age events were placed into an ordinal sequence and calibrated to the geological time-scale to reveal a high-resolution species richness record for the first 80% of the Neoproterozoic Era. Major features of this record include an increase in species richness ~805 Ma, sustained high richness levels until a decrease ~770 Ma and a short-lived increase ~760 Ma before a steep decline ~750 Ma. The findings of the two studies described above can be placed within the context of this broader synthesis: the diverse assemblage of the Alinya Formation is representative of the richness peak between ~805 and 775 Ma and the successions recording the Sturtian glacial and interglacial assemblages in Australia and Svalbard are indicative of the extended nadir that began ~750 Ma with a recovery in species richness delayed until after the termination of the second (Marinoan) glacial event.These three studies, together, describe a broad view of the early to middle Neoproterozoic Era and detail important vignettes within that story. From a more detailed and temporally constrained record of the Neoproterozoic biosphere, relationships between biotic and abiotic events during this transformative time can become better understood

Localization and Mapping from Shore Contours and Depth

This work examines the problem of solving SLAM in aquatic environments using an unmanned surface vessel under conditions that restrict global knowledge of the robot's pose. These conditions refer specifically to the absence of a global positioning system to estimate position, a poor vehicle motion model, and absence of magnetic field to estimate absolute heading. These conditions are present in terrestrial environments where GPS satellite reception is occluded by surrounding structures and magnetic inference affects compass measurements. Similar conditions are anticipated in extra-terrestrial environments such as on Titan which lacks the infrastructure necessary for traditional positioning sensors and the unstable magnetic core renders compasses useless. This work develops a solution to the SLAM problem that utilizes shore features coupled with information about the depth of the water column. The approach is validated experimentally using an autonomous surface vehicle utilizing omnidirectional video and SONAR, results are compared to GPS ground truth