Temporal archetypal analysis for action segmentation

Unsupervised learning of invariant representations that efficiently describe high-dimensional time series has several applications in dynamic visual data analysis. Clearly, the problem becomes more challenging when dealing with multiple time series arising from different modalities. A prominent example of this multimodal setting is the human motion which can be represented by multimodal time series of pixel intensities, depth maps, and motion capture data. Here, we study, for the first time, the problem of unsupervised learning of temporally and modality invariant informative representations, referred to as archetypes, from multiple time series originating from different modalities. To this end a novel method, coined as temporal archetypal analysis, is proposed. The performance of the proposed method is assessed by conducting experiments in unsupervised action segmentation. Experimental results on three different real world datasets using single modal and multimodal visual representations indicate the robustness and effectiveness of the proposed methods, outperforming compared state-of-the-art methods by a large, in most of the cases, margin

Temporal archetypal analysis for action segmentation

Unsupervised learning of invariant representations that efficiently describe high-dimensional time series has several applications in dynamic visual data analysis. Clearly, the problem becomes more challenging when dealing with multiple time series arising from different modalities. A prominent example of this multimodal setting is the human motion which can be represented by multimodal time series of pixel intensities, depth maps, and motion capture data. Here, we study, for the first time, the problem of unsupervised learning of temporally and modality invariant informative representations, referred to as archetypes, from multiple time series originating from different modalities. To this end a novel method, coined as temporal archetypal analysis, is proposed. The performance of the proposed method is assessed by conducting experiments in unsupervised action segmentation. Experimental results on three different real world datasets using single modal and multimodal visual representations indicate the robustness and effectiveness of the proposed methods, outperforming compared state-of-the-art methods by a large, in most of the cases, margin

Partial differential equations for self-organization in cellular and developmental biology

Understanding the mechanisms governing and regulating the emergence of structure and heterogeneity within cellular systems, such as the developing embryo, represents a multiscale challenge typifying current integrative biology research, namely, explaining the macroscale behaviour of a system from microscale dynamics. This review will focus upon modelling how cell-based dynamics orchestrate the emergence of higher level structure. After surveying representative biological examples and the models used to describe them, we will assess how developments at the scale of molecular biology have impacted on current theoretical frameworks, and the new modelling opportunities that are emerging as a result. We shall restrict our survey of mathematical approaches to partial differential equations and the tools required for their analysis. We will discuss the gap between the modelling abstraction and biological reality, the challenges this presents and highlight some open problems in the field

Voice and poetry as inspiration and material in acousmatic composition

This thesis combines both practice-based research, in the form of acousmatic composition, and theoretical research, addressing voice and poetry both as inspiration and material. It includes a portfolio of original compositions and a written text with aesthetic ideas that informed the compositional process. The aim of the research was to propose a particular creative strategy, based on Chilean poet Vicente Huidobro’s aesthetic theory; a system which aims to create artistic works independent of real world by taking materials from reality and combining them in unexpected ways through an equilibrium between rationality and intuition. This theory, alongside various other theoretical and artistic sources informing the creative process, is explained in a section entitled Compositional Rationale. The broader thesis is divided into two parts, each starting with a methodology relating to the compositions described within: Part 1: Octophonic cycle La lumière artificielle and Part 2: Three acousmatic tributes. In order to examine how the Compositional Rationale operates within the portfolio’s pieces, an analytical methodology has been proposed. This is described in an Analytical methodology section and considers the use of two parts of the tripartite model proposed by Nattiez (1990) and developed for electroacoustic music by Roy (2004). The two parts of the tripartite model are poietic analysis and neutral analysis. The first describes the creative process and compositional considerations of the author, and the second details the constitutive elements of each piece within five areas; Pierre Schaeffer’s notion of sound objects (1966), Denis Smalley’s notion of spectromorphological functions (1997), levels of spatial function by Annette Vande Gorne (2010), and finally two more types of analyses developed by the author: voice type and speech-sound type. Taken as a whole, the analysis demonstrates the structural constitution of each piece, and thus shows how Huidobro’s creative system, called creacionismo, has been applied successfully to acousmatic composition, generating the notion of acousmatic-creationist as nomenclature for the process. This is the main outcome of this thesis, a new artistic strategy which balances rationality and intuition within acousmatic composition and places poetry as a driven force in the use of voice, merging artistic practice and theory in a recursive action

Computational estimation of haemodynamics and tissue stresses in abdominal aortic aneurysms

'o e Abdominal aortic aneurysm is a vascular disease involving a focal dilation of the aorta. The exact cause is unknown but possibilities include infection and weakening of the connective tissue. Risk factors include a history of atherosclerosis, current smoking and a close relative with the disease. Although abdominal aortic aneurysm can affect anyone, it is most often seen in older men, and may be present in up to 5.9 % of the population aged 80 years. Biomechanical factors such as tissue stresses and shear stresses have been shown to play a part in aneurysm progression, although the specific mechanisms are still to be determined. The growth rate of the abdominal aortic aneurysm has been found to correlate with the peak stress in the aneurysm wall and the blood flow is thought to influence disease development. In order to resolve the connections between biology and biomechanics, accurate estimations of the forces involved are required. The first part of this thesis assesses the use of computational fluid dynamics for modelling haemodynamics in abdominal aortic aneurysms. Boundary conditions from the literature o

A Transformational Approach for Musical Variation

This article is associated with a broad research addressing musical variation, whose main objective is the systematization of the analysis through the elaboration of an original analytical model. A new version of this model proposes a formal approach based on principles of the transformational theory. The present article is focused in the notion of variation isolated from a contextual framework (that is, out of temporal perspectives), setting the basis for further explorations. .Some original concepts, like derivative work, derivative space, attributes, among others, provide means for measurement of similarity relations between referential and derived musical ideas, as well as graphic representation for these relationships.This article is associated with a broad research addressing musical variation, whose main objective is the systematization of the analysis through the elaboration of an original analytical model. A new version of this model proposes a formal approach based on principles of the transformational theory. The present article is focused on the notion of variation isolated from a contextual framework (that is, out of temporal perspectives), setting the basis for further exploration. Some original concepts, like derivative work, derivative space, attributes, among others, provide means for measurement of similarity relations between referential and derived musical ideas, as well as graphic representation for these relationships