Radar UAV and Bird Signature comparisons with Micro-Doppler

This chapter reviews the similarities and differences between micro Unmanned Aerial Vehicles (UAVs), also referred to as drones, and bird targets from the signals they present to radar sensors. With the increasing usage of UAV platforms in both military and civilian applications, the demand for the ability to sense drone locations and discriminate them from background clutter and non-drone targets is becoming a vital requirement. A comparable target in size, speed and Radar Cross Section (RCS) is a bird. These are present almost everywhere that radar systems have to operate and have been detected by radar since the early origin of radar engineering. Due to the similarity in radar signature birds can cause common misclassification between them and the priority drone targets which has been identified as a current key challenge in radar sensing. In this chapter radar bird and drone signature research is initially summarised, then a fundamental model that represents the key contributions from drone rotor blades is introduced and compared to real measurements. Laboratory measurements of quadcopter rotor blade signatures with across 4 linear polarisations are then investigated in order to evaluate the trend of Signal-to-Noise-Ratio (SNR) vs. aspect angle. Next bird signatures from two separate radar systems are shown and compared to drone targets also present in the captures which are of comparable size and RCS. The outputs of all research presented are then summarised in the concluding remarks

Sound design for the opera composer: concepts and methods

Sound design has become an important part of theatre, film and contemporary opera, and a creative discipline in its own right. A pattern of convergence between music and sound has emerged during the last two decades across these disciplines. My project investigates this convergence, reviewing the literature and recent sound practice in opera, theatre (particularly Composed Theatre) and film (both live action and animation). This review explores concepts including soundscape, immersion, acousmêtre, the sonic Umwelt and phenomenologies and semiotics of sound through the writings of Michel Chion, Nicholas Cook, R Murray Shafer, Theo Van Leeuwen and others. It also examines the role of sound in the work of practitioners such as composers Steve Reich, John Adams, Heiner Goebbels and Anthony Davis and their collaborators, and sound designers such as Gary Rydstrom, Nicolas Becker and Kristian Selin Eidnes Andersen in film, and Ross Brown and Complicité in theatre. From this review I draw out features, or modalities, of existing sound practice with the potential to be integrated into opera composition. I define these modalities as: sound as environment, sound as music, sound as action, sound as inner voice, and sound as sign. These modalities form a theoretical basis upon which to develop a method of opera composition in which sound design is integral. This forms the focus of this project, in particular the objective of moving beyond current practice to create opera with integrated sound design that exemplifies a dynamic and transactional relationship between sound, music and other elements. My three chamber operas Her face was of flowers, Vicky and Albert and The Trilobite, Or The Fall of Mr Williams are the result. I discuss the compositional process and performance history of these three pieces in relation to my five modalities of sound, and the models of sound practice that inspired them. Finally, I draw conclusions from the processes of composing, rehearsing and performing these operas that point the way to further development and exploration of opera with integrated sound design, both in my practice and elsewhere, offering the opera composer a new perspective on working with sound

LOUDER THAN WORDS: VOICING, SOUNDING, AND LISTENING TO DEAFNESS IN A QUIET PLACE

LOUDER THAN WORDS: VOICING, SOUNDING, AND LISTENING TO DEAFNESS IN A QUIET PLAC

No One Flunks Museum: An Overview of Learning Theory and its Implementation in Formal and Informal History Education

The transition of museums from institutions for the knowledgeable to places for those seeking knowledge has brought about a need for those educating in museums to better understand the ways in which people learn. This paper introduces and explains theories, psychological and educational, that are applicable to learning such as Constructivism, Multiple Intelligences, and the Contextual Model of Learning. Observations of informal and formal history and social studies lessons or programs presented to students ages 3-16 provide the framework for understanding how well these theories of learning are being implemented in the museum. Comparison of history museum programs (informal education) with social studies school lessons (formal education) has demonstrated that both are succeeding as learning institutions, however the informal educational programs often have the ability to reach a more diverse audience of learners than formal educational programs do. If the goal of museums and schools is to educate each student/visitor equally then the future seems clear-museums and schools must work together to understand the strengths and restrictions each has to ultimately ensure that no child is left behind

Experience and knowledge

Experience is the source of empirical knowledge. Does this require that experience itself be knowledge? My answer to the question is affirmative. Experience, in so far as it is the source of empirical knowledge, has to be itself knowledge. Following the traditional understanding of knowledge, this means that experience as the source of knowledge is a kind of justified true belief. This I call the gnostic conception of experience, or gnosticism for short. The aim of the thesis is to argue for gnosticism. The thesis consists of nine chapters. Chapter 1 proposes gnosticism and examines some historical traditions from the gnosticist point of view. Chapter 2 defends a version of traditional understanding of knowledge on which gnosticismis based. Chapter 3 rejects nongnosticism by arguing against nonconceptualism. It is argued that nonconceptual experience cannot play a justificatory role for thought, since there is no systematic relation between nonconceptual experience and thought. Chapter 4 rejects quasi-gnosticism by arguing against conceptualism. Based on the doxastic criterion of justification, the chapter challenges the justificatory role of nondoxatic conceptual experience. Chapter 5 explores the relationship between experience and concept and argues that experience and concept are constitutive of each other. Chapter 6 proposes and argues for doxasticism which says that experience is belief about the world. Chapter 7 defends doxasticism against the disbelief objection which says we do not always believe what we experience. Chapter 8 argues that the voluntariness of belief does not undermine doxasticism since experience is an active, rational exploration of the world. With doxasticism established, chapter 9 returns to gnosticism by tackling the problem of the justification of experience. It is argued that experience can be justified as true without being inferential and is in this sense the foundation of empirical knowledge

Spatial Hearing with Simultaneous Sound Sources: A Psychophysical Investigation

This thesis provides an overview of work conducted to investigate human spatial hearing in situations involving multiple concurrent sound sources. Much is known about spatial hearing with single sound sources, including the acoustic cues to source location and the accuracy of localisation under different conditions. However, more recently interest has grown in the behaviour of listeners in more complex environments. Concurrent sound sources pose a particularly difficult problem for the auditory system, as their identities and locations must be extracted from a common set of sensory receptors and shared computational machinery. It is clear that humans have a rich perception of their auditory world, but just how concurrent sounds are processed, and how accurately, are issues that are poorly understood. This work attempts to fill a gap in our understanding by systematically examining spatial resolution with multiple sound sources. A series of psychophysical experiments was conducted on listeners with normal hearing to measure performance in spatial localisation and discrimination tasks involving more than one source. The general approach was to present sources that overlapped in both frequency and time in order to observe performance in the most challenging of situations. Furthermore, the role of two primary sets of location cues in concurrent source listening was probed by examining performance in different spatial dimensions. The binaural cues arise due to the separation of the two ears, and provide information about the lateral position of sound sources. The spectral cues result from location-dependent filtering by the head and pinnae, and allow vertical and front-rear auditory discrimination. Two sets of experiments are described that employed relatively simple broadband noise stimuli. In the first of these, two-point discrimination thresholds were measured using simultaneous noise bursts. It was found that the pair could be resolved only if a binaural difference was present; spectral cues did not appear to be sufficient. In the second set of experiments, the two stimuli were made distinguishable on the basis of their temporal envelopes, and the localisation of a designated target source was directly examined. Remarkably robust localisation was observed, despite the simultaneous masker, and both binaural and spectral cues appeared to be of use in this case. Small but persistent errors were observed, which in the lateral dimension represented a systematic shift away from the location of the masker. The errors can be explained by interference in the processing of the different location cues. Overall these experiments demonstrated that the spatial perception of concurrent sound sources is highly dependent on stimulus characteristics and configurations. This suggests that the underlying spatial representations are limited by the accuracy with which acoustic spatial cues can be extracted from a mixed signal. Three sets of experiments are then described that examined spatial performance with speech, a complex natural sound. The first measured how well speech is localised in isolation. This work demonstrated that speech contains high-frequency energy that is essential for accurate three-dimensional localisation. In the second set of experiments, spatial resolution for concurrent monosyllabic words was examined using similar approaches to those used for the concurrent noise experiments. It was found that resolution for concurrent speech stimuli was similar to resolution for concurrent noise stimuli. Importantly, listeners were limited in their ability to concurrently process the location-dependent spectral cues associated with two brief speech sources. In the final set of experiments, the role of spatial hearing was examined in a more relevant setting containing concurrent streams of sentence speech. It has long been known that binaural differences can aid segregation and enhance selective attention in such situations. The results presented here confirmed this finding and extended it to show that the spectral cues associated with different locations can also contribute. As a whole, this work provides an in-depth examination of spatial performance in concurrent source situations and delineates some of the limitations of this process. In general, spatial accuracy with concurrent sources is poorer than with single sound sources, as both binaural and spectral cues are subject to interference. Nonetheless, binaural cues are quite robust for representing concurrent source locations, and spectral cues can enhance spatial listening in many situations. The findings also highlight the intricate relationship that exists between spatial hearing, auditory object processing, and the allocation of attention in complex environments

Spatial Hearing with Simultaneous Sound Sources: A Psychophysical Investigation

This thesis provides an overview of work conducted to investigate human spatial hearing in situations involving multiple concurrent sound sources. Much is known about spatial hearing with single sound sources, including the acoustic cues to source location and the accuracy of localisation under different conditions. However, more recently interest has grown in the behaviour of listeners in more complex environments. Concurrent sound sources pose a particularly difficult problem for the auditory system, as their identities and locations must be extracted from a common set of sensory receptors and shared computational machinery. It is clear that humans have a rich perception of their auditory world, but just how concurrent sounds are processed, and how accurately, are issues that are poorly understood. This work attempts to fill a gap in our understanding by systematically examining spatial resolution with multiple sound sources. A series of psychophysical experiments was conducted on listeners with normal hearing to measure performance in spatial localisation and discrimination tasks involving more than one source. The general approach was to present sources that overlapped in both frequency and time in order to observe performance in the most challenging of situations. Furthermore, the role of two primary sets of location cues in concurrent source listening was probed by examining performance in different spatial dimensions. The binaural cues arise due to the separation of the two ears, and provide information about the lateral position of sound sources. The spectral cues result from location-dependent filtering by the head and pinnae, and allow vertical and front-rear auditory discrimination. Two sets of experiments are described that employed relatively simple broadband noise stimuli. In the first of these, two-point discrimination thresholds were measured using simultaneous noise bursts. It was found that the pair could be resolved only if a binaural difference was present; spectral cues did not appear to be sufficient. In the second set of experiments, the two stimuli were made distinguishable on the basis of their temporal envelopes, and the localisation of a designated target source was directly examined. Remarkably robust localisation was observed, despite the simultaneous masker, and both binaural and spectral cues appeared to be of use in this case. Small but persistent errors were observed, which in the lateral dimension represented a systematic shift away from the location of the masker. The errors can be explained by interference in the processing of the different location cues. Overall these experiments demonstrated that the spatial perception of concurrent sound sources is highly dependent on stimulus characteristics and configurations. This suggests that the underlying spatial representations are limited by the accuracy with which acoustic spatial cues can be extracted from a mixed signal. Three sets of experiments are then described that examined spatial performance with speech, a complex natural sound. The first measured how well speech is localised in isolation. This work demonstrated that speech contains high-frequency energy that is essential for accurate three-dimensional localisation. In the second set of experiments, spatial resolution for concurrent monosyllabic words was examined using similar approaches to those used for the concurrent noise experiments. It was found that resolution for concurrent speech stimuli was similar to resolution for concurrent noise stimuli. Importantly, listeners were limited in their ability to concurrently process the location-dependent spectral cues associated with two brief speech sources. In the final set of experiments, the role of spatial hearing was examined in a more relevant setting containing concurrent streams of sentence speech. It has long been known that binaural differences can aid segregation and enhance selective attention in such situations. The results presented here confirmed this finding and extended it to show that the spectral cues associated with different locations can also contribute. As a whole, this work provides an in-depth examination of spatial performance in concurrent source situations and delineates some of the limitations of this process. In general, spatial accuracy with concurrent sources is poorer than with single sound sources, as both binaural and spectral cues are subject to interference. Nonetheless, binaural cues are quite robust for representing concurrent source locations, and spectral cues can enhance spatial listening in many situations. The findings also highlight the intricate relationship that exists between spatial hearing, auditory object processing, and the allocation of attention in complex environments

Doctor of Philosophy

dissertationInfluenced by the continued growth of the interdisciplinary field of sound studies, my dissertation examines sounds and soundscapes in several prose works of Western American literature. Literary Soundscapes of the American West examines literary sounds-the collective, but varied, representations of sound, silence, and voice in literature-that represent intimate, affective, and always-changing relationships between people and places in the contemporary American West. I argue that Sherman Alexie, Cormac McCarthy, Terry Tempest Williams, and Charles Bowden use literary sounds to encourage-and potentially activate-what I call an audile mode of attention, which underscores sound as fundamental to people's understanding of place as well as their relationship to space generally. My analysis examines literary sounds that resonate in representations of specific Western locales: a Northwestern metropolis, the Southwestern redrock desert, and the U.S.-Mexican borderlands. Literary sounds do not operate identically in each of my primary texts. In fiction, such as Alexie's Indian Killer and McCarthy's The Crossing, representations of sound occupy an understated and subordinate position in the text. In contrast to these fictional works, Williams' Red and Bowden's Murder City demand that readers attend to sound because it represents local knowledge about pressing ethical concerns. In my analysis of contemporary Western literature, I employ critical regionalism, sound studies, and affect theory and argue that Alexie, McCarthy, Williams, and Bowden produce literary sounds that represent the tensions between various spatial scales (the personal, the local, the regional, and the global) in twentieth- and twenty-first century Western places. By combining the overlapping concerns of these three critical paradigms with my interest in representations of place in contemporary Western American literature, my dissertation evaluates the productive potential of excess in a selected body of literature. The particular excess that I consider here is made up of a relatively immaterial and transient form, sound and, to be more specific, sounds produced in literature. To say that sound, in everyday life or in literature, constitutes excess is not to suggest that it is not necessary to or always already resonant in our interpretations of and experiences with place and space. Rather, I argue that sounds produce excess by activating untapped potential and calling upon readers and listeners to identify in place those contingent truths and realities that escape our notice when we view place as a closed and contained form