MODELLING GAMAKAS OF CARNATIC MUSIC AS A SYNTHESIZER FOR SPARSE PRESCRIPTIVE NOTATION

Ph.DDOCTOR OF PHILOSOPH

Content-based music structure analysis

Ph.DDOCTOR OF PHILOSOPH

A Cross-Cultural Analysis of Music Structure

PhDMusic signal analysis is a research field concerning the extraction of meaningful information from musical audio signals. This thesis analyses the music signals from the note-level to the song-level in a bottom-up manner and situates the research in two Music information retrieval (MIR) problems: audio onset detection (AOD) and music structural segmentation (MSS). Most MIR tools are developed for and evaluated on Western music with specific musical knowledge encoded. This thesis approaches the investigated tasks from a cross-cultural perspective by developing audio features and algorithms applicable for both Western and non-Western genres. Two Chinese Jingju databases are collected to facilitate respectively the AOD and MSS tasks investigated. New features and algorithms for AOD are presented relying on fusion techniques. We show that fusion can significantly improve the performance of the constituent baseline AOD algorithms. A large-scale parameter analysis is carried out to identify the relations between system configurations and the musical properties of different music types. Novel audio features are developed to summarise music timbre, harmony and rhythm for its structural description. The new features serve as effective alternatives to commonly used ones, showing comparable performance on existing datasets, and surpass them on the Jingju dataset. A new segmentation algorithm is presented which effectively captures the structural characteristics of Jingju. By evaluating the presented audio features and different segmentation algorithms incorporating different structural principles for the investigated music types, this thesis also identifies the underlying relations between audio features, segmentation methods and music genres in the scenario of music structural analysis.China Scholarship Council EPSRC C4DM Travel Funding, EPSRC Fusing Semantic and Audio Technologies for Intelligent Music Production and Consumption (EP/L019981/1), EPSRC Platform Grant on Digital Music (EP/K009559/1), European Research Council project CompMusic, International Society for Music Information Retrieval Student Grant, QMUL Postgraduate Research Fund, QMUL-BUPT Joint Programme Funding Women in Music Information Retrieval Grant

Towards the Automatic Analysis of Metric Modulations

PhDThe metrical structure is a fundamental aspect of music, yet its automatic analysis from audio recordings remains one of the great challenges of Music Information Retrieval (MIR) research. This thesis is concerned with addressing the automatic analysis of changes of metrical structure over time, i.e. metric modulations. The evaluation of automatic musical analysis methods is a critical element of the MIR research and is typically performed by comparing the machine-generated estimates with human expert annotations, which are used as a proxy for ground truth. We present here two new datasets of annotations for the evaluation of metrical structure and metric modulation estimation systems. Multiple annotations allowed for the assessment of inter-annotator (dis)agreement, thereby allowing for an evaluation of the reference annotations used to evaluate the automatic systems. The rhythmogram has been identified in previous research as a feature capable of capturing characteristics of rhythmic content of a music recording. We present here a direct evaluation of its ability to characterise the metrical structure and as a result we propose a method to explicitly extract metrical structure descriptors from it. Despite generally good and increasing performance, such rhythm features extraction systems occasionally fail. When unpredictable, the failures are a barrier to usability and development of trust in MIR systems. In a bid to address this issue, we then propose a method to estimate the reliability of rhythm features extraction. Finally, we propose a two-fold method to automatically analyse metric modulations from audio recordings. On the one hand, we propose a method to detect metrical structure changes from the rhythmogram feature in an unsupervised fashion. On the other hand, we propose a metric modulations taxonomy rooted in music theory that relies on metrical structure descriptors that can be automatically estimated. Bringing these elements together lays the ground for the automatic production of a musicological interpretation of metric modulations.EPSRC award 1325200 and Omnifone Ltd

SIMULATION MODELING OF FLIGHT DYNAMICS, CONTROL AND TRAJECTORY OPTIMIZATION OF ROTORCRAFT TOWING SUBMERGED LOADS

This work presents the mathematical modeling and analysis of helicopters towing submerged loads using long cables for sub-surface object detection when surface-based vessels cannot operate safely. A geometrically exact model of rotating beams is derived, and used to represent both the cable dynamics and rotor blade dynamics. Flight dynamics and trim conditions for an axially flexible straight cable and a curved cable are separately formulated for a general case of helical climbing turns, and used to cross-validate each other. In steady flight, the trim longitudinal dynamics of the submerged load produces down-forces from towed body fins, increasing the apparent weight of the tow system. Cable and towed body drag manifest as increases in the effective equivalent flat- plate area, necessitating excessive nose-down helicopter trim pitch attitudes (-6◦ ) and causing pilot discomfort. Excessive pitch attitudes can be avoided using aft offset of the helicopter tow point, or the deployment of longer cables in combination with pitching fins to regulate towed body depth. In steady level turning flight, cable and towed body drag result in the submerged load turning with a consistently smaller radius than the helicopter. Depth regulation in turning flight using pitching fins is less effective than in forward flight due to increased cable drag opposing larger down-forces. Analysis of linearized models showed that the helicopter frequency response to pilot inputs is unaffected by the addition of the cable and towed body above 1 rad/s. The low-frequency response magnitude reduces with increasing hydrodynamic drag on the cable and towed body, and is unaffected by cable structural properties due to over-damped stabilization from hydrodynamics. The swashplate inputs required to guide the towed body along a "tear-drop" shaped trajectory are obtained using a two-stage process. The motions of the tow point that guide the submerged load along the target path are obtained using an optimization process. The system target states are generated based on these tow point motions, and an LQR controller is used to guide the helicopter along its target path. Trim rotor inflows from the vortex wake model are obtained at the various equilibrium points used to construct helicopter target states, interpolated and applied as "delta" corrections to the dynamic inflow model. Blade elastic twist has a significant effect on rotor power predictions and the steady hub loads, while flap bending elasticity acts as a vibration absorber to attenuate the oscillatory component of hub rolling and pitching moments

An Anthropology of Intellectual Exchange: Interactions, Transactions and Ethics in Asia and Beyond

Dialogues, encounters and interactions through which particular ways of knowing, understanding and thinking about the world are forged lie at the centre of anthropology. Such ‘intellectual exchange’ is also central to anthropologists’ own professional practice: from their interactions with research participants and modes of pedagogy to their engagements with each other and scholars from adjacent disciplines. This collection of essays explores how such processes might best be studied cross-culturally. Foregrounding the diverse interactions, ethical reasoning, and intellectual lives of people from across the continent of Asia, the volume develops an anthropology of intellectual exchange itself