908 research outputs found
Geometric Data Analysis: Advancements of the Statistical Methodology and Applications
Data analysis has become fundamental to our society and comes in multiple facets and approaches. Nevertheless, in research and applications, the focus was primarily on data from Euclidean vector spaces. Consequently, the majority of methods that are applied today are not suited for more general data types. Driven by needs from fields like image processing, (medical) shape analysis, and network analysis, more and more attention has recently been given to data from non-Euclidean spaces–particularly (curved) manifolds. It has led to the field of geometric data analysis whose methods explicitly take the structure (for example, the topology and geometry) of the underlying space into account.
This thesis contributes to the methodology of geometric data analysis by generalizing several fundamental notions from multivariate statistics to manifolds. We thereby focus on two different viewpoints.
First, we use Riemannian structures to derive a novel regression scheme for general manifolds that relies on splines of generalized BĂ©zier curves. It can accurately model non-geodesic relationships, for example, time-dependent trends with saturation effects or cyclic trends. Since BĂ©zier curves can be evaluated with the constructive de Casteljau algorithm, working with data from manifolds of high dimensions (for example, a hundred thousand or more) is feasible. Relying on the regression, we further develop
a hierarchical statistical model for an adequate analysis of longitudinal data in manifolds, and a method to control for confounding variables.
We secondly focus on data that is not only manifold- but even Lie group-valued, which is frequently the case in applications. We can only achieve this by endowing the group with an affine connection structure that is generally not Riemannian. Utilizing it, we derive generalizations of several well-known dissimilarity measures between data distributions that can be used for various tasks, including hypothesis testing. Invariance under data translations is proven, and a connection to continuous distributions is given for one measure.
A further central contribution of this thesis is that it shows use cases for all notions in real-world applications, particularly in problems from shape analysis in medical imaging and archaeology. We can replicate or further quantify several known findings for shape changes of the femur and the right hippocampus under osteoarthritis and Alzheimer's, respectively. Furthermore, in an archaeological application, we obtain new insights into the construction principles of ancient sundials. Last but not least, we use the geometric structure underlying human brain connectomes to predict cognitive scores. Utilizing a sample selection procedure, we obtain state-of-the-art results
An analytical framework of tissue-patch clustering for quantifying phenotypes of whole slide images
Histopathology is considered the most practical diagnostic method for patient with early stage cancer. This is because at the very first pre-screening, patient’s tissue samples are delivered to pathologist for examining evidence of cancer. Computational scientists aid pathologist by heavily producing research on machine learning-based morphological pattern recognition of tissue image. Many data modelling investigations on histopathology have been conducted in supervised manner and some of them were further employed in real-life clinical diagnosis. This study proposes an approach to developing clusters of tissue tile. The main aim is to obtain ’high-quality clusters’ with respect to phenotypic annotations. In order to achieve this goal, two colorectal datasets namely 100k-nct and TCGA-COAD are experimented, one of which is directly annotated with tissue type, and other dataset is annotated through derivation from patient metadata, quiescent status. Four main independent variables were explored in this study (i) feature extraction by Resnet50, InceptionV3, VGG16 and an unsupervised generative model, PathologyGAN. (ii) feature space transformer including original feature, 3D PCA feature and 3D-UMAP feature and (iii) clustering algorithms namely Gaussian Mixture Model and Hierarchical clustering and their primary hyper-parameters. As a result, Resnet50 empowered by UMAP outperformed the most in clustering tissue type on 100k-nct dataset at v-measure of 0.74. The other dataset of which quiescent status is derived from patients encountered nearly zero in v-measure. However, clustering this quiescence-based dataset on 3D-UMAP Pathology-GAN yielded far higher V-measure than the rest of cluster configurations and illustrates ability to capture quiescence-related phenotype through visualisation
Musiktheorie als interdisziplinäres Fach: 8. Kongress der Gesellschaft für Musiktheorie Graz 2008
Im Oktober 2008 fand an der Universität für Musik und darstellende Kunst Graz (KUG) der 8. Kongress der Gesellschaft für Musiktheorie (GMTH) zum Thema »Musiktheorie als interdisziplinäres Fach« statt. Die hier vorgelegten gesammelten Beiträge akzentuieren Musiktheorie als multiperspektivische wissenschaftliche Disziplin in den Spannungsfeldern Theorie/Praxis, Kunst/Wissenschaft und Historik/Systematik. Die sechs Kapitel ergründen dabei die Grenzbereiche zur Musikgeschichte, Musikästhetik, zur Praxis musikalischer Interpretation, zur kompositorischen Praxis im 20. und 21. Jahrhundert, zur Ethnomusikologie sowie zur Systematischen Musikwissenschaft. Insgesamt 45 Aufsätze, davon 28 in deutscher, 17 in englischer Sprache, sowie die Dokumentation einer Podiumsdiskussion zeichnen in ihrer Gesamtheit einen höchst lebendigen und gegenwartsbezogenen Diskurs, der eine einzigartige Standortbestimmung des Fachs Musiktheorie bietet.The 8th congress of the Gesellschaft für Musiktheorie (GMTH) took place in October 2008 at the University for Music and Dramatic Arts Graz (KUG) on the topic »Music Theory and Interdisciplinarity«. The collected contributions characterize music theory as a multi-faceted scholarly discipline at the intersection of theory/practice, art/science and history/system. The six chapters explore commonalties with music history, music aesthetics, musical performance, compositional practice in twentieth- and twenty-first-century music, ethnomusicology and systematic musicology. A total of 45 essays (28 in German, 17 in English) and the documentation of a panel discussion form a vital discourse informed by contemporaneous issues of research in a broad number of fields, providing a unique overview of music theory today. A comprehensive English summary appears at the beginning of all contributions
Behavior quantification as the missing link between fields: Tools for digital psychiatry and their role in the future of neurobiology
The great behavioral heterogeneity observed between individuals with the same
psychiatric disorder and even within one individual over time complicates both
clinical practice and biomedical research. However, modern technologies are an
exciting opportunity to improve behavioral characterization. Existing
psychiatry methods that are qualitative or unscalable, such as patient surveys
or clinical interviews, can now be collected at a greater capacity and analyzed
to produce new quantitative measures. Furthermore, recent capabilities for
continuous collection of passive sensor streams, such as phone GPS or
smartwatch accelerometer, open avenues of novel questioning that were
previously entirely unrealistic. Their temporally dense nature enables a
cohesive study of real-time neural and behavioral signals.
To develop comprehensive neurobiological models of psychiatric disease, it
will be critical to first develop strong methods for behavioral quantification.
There is huge potential in what can theoretically be captured by current
technologies, but this in itself presents a large computational challenge --
one that will necessitate new data processing tools, new machine learning
techniques, and ultimately a shift in how interdisciplinary work is conducted.
In my thesis, I detail research projects that take different perspectives on
digital psychiatry, subsequently tying ideas together with a concluding
discussion on the future of the field. I also provide software infrastructure
where relevant, with extensive documentation.
Major contributions include scientific arguments and proof of concept results
for daily free-form audio journals as an underappreciated psychiatry research
datatype, as well as novel stability theorems and pilot empirical success for a
proposed multi-area recurrent neural network architecture.Comment: PhD thesis cop
A Survey on Continual Semantic Segmentation: Theory, Challenge, Method and Application
Continual learning, also known as incremental learning or life-long learning,
stands at the forefront of deep learning and AI systems. It breaks through the
obstacle of one-way training on close sets and enables continuous adaptive
learning on open-set conditions. In the recent decade, continual learning has
been explored and applied in multiple fields especially in computer vision
covering classification, detection and segmentation tasks. Continual semantic
segmentation (CSS), of which the dense prediction peculiarity makes it a
challenging, intricate and burgeoning task. In this paper, we present a review
of CSS, committing to building a comprehensive survey on problem formulations,
primary challenges, universal datasets, neoteric theories and multifarious
applications. Concretely, we begin by elucidating the problem definitions and
primary challenges. Based on an in-depth investigation of relevant approaches,
we sort out and categorize current CSS models into two main branches including
\textit{data-replay} and \textit{data-free} sets. In each branch, the
corresponding approaches are similarity-based clustered and thoroughly
analyzed, following qualitative comparison and quantitative reproductions on
relevant datasets. Besides, we also introduce four CSS specialities with
diverse application scenarios and development tendencies. Furthermore, we
develop a benchmark for CSS encompassing representative references, evaluation
results and reproductions, which is available
at~\url{https://github.com/YBIO/SurveyCSS}. We hope this survey can serve as a
reference-worthy and stimulating contribution to the advancement of the
life-long learning field, while also providing valuable perspectives for
related fields.Comment: 20 pages, 12 figures. Undergoing Revie
- …