Mean Field Approaches to Independent Component Analysis

We develop mean field approaches for probabilistic independent component analysis (ICA). The sources are estimated from the mean of their posterior distribution and the mixing matrix (and noise level) is estimated by maximum a posteriori (MAP). The latter requires the computation of (a good approximation to) the correlations between sources. For this purpose we investigate three increasingly advanced mean field methods: variational, linear response and adaptive TAP and test the resulting algorithms on a number of problems. On synthetic data the advanced mean field approaches are able to recover the correct mixing matrix in cases where the variational mean field theory fails. For hand-written digits, sparse encoding is achieved using non-negative source and mixing priors. For speech, the mean field method is able to separate in the underdetermined (overcomplete) case of two sensors and three sources. One major advantage of the proposed method is its generality and implementational simplicity. Finally, we point out several possible extensions of the approaches developed here

C. Historiography : Danish Research from Johannes Østrup (1893) to the Palmyra Portrait Project

Since 2012 the Palmyra Portrait Project research group based at Aarhus University has been working on compiling as comprehensive a corpus of palmyrene funerary sculpture as possible . At present the corpus includes more than 3300 portraits, which is far beyond what any scholar thought still existed of these portraits . The corpus is currently being prepared for final publication. The corpus makes up the largest group of portraits stemming from the Roman period and coming from outside Rome its..

Tractable Inference for Probabilistic Data Models

Based on ideas from statistical physics, we present an approximation technique for probabilistic data models with a large number of hidden variables. We give examples for two non–trivial applications.

Psychotropic drug use following venous thromboembolism versus diabetes mellitus in adolescence or young adulthood: A Danish nationwide cohort study

© Author(s) (or their employer(s)) 2018. Objectives Critical and chronic illness in youth such as diabetes can lead to impaired mental health. Despite the potentially traumatic and life-Threatening nature of venous thromboembolism (VTE), the long-Term mental health of adolescents and young adults with VTE is unclear. We compared the long-Term mental health of adolescents and young adults with VTE versus adolescents and young adults with insulin-dependent diabetes mellitus (IDDM) using psychotropic drug purchase as proxy for mental health. Design Nationwide registry-based cohort study. Setting Denmark 1997-2015. Participants All patients aged 13-33 years with an incident diagnosis of VTE (n=5065) or IDDM (n=6609). Exposure First time primary hospital diagnosis of VTE or IDDM. Primary and secondary outcome measures Adjusted absolute risk and risk difference at 1 and 5 years follow-up for first psychotropic drug purchase comparing patients with VTE and patients with IDDM. Results The absolute 1 year risk of psychotropic drug use was 6.2% among VTE patients versus 3.6% among patients with IDDM, at 5 years this was 19.3%-14.7%, respectively. After adjusting for the effect of sex, age and risk factors for VTE this corresponded to a 1 year risk differences of 1.9% (95 % CI 0.1% to 3.3%). At 5 years follow-up the risk difference was 1.9% (95% CI 0.5% to 3.3%). Conclusion One-fifth of adolescents and young adults with incident VTE had claimed a prescription for a psychotropic drug within 5 years, a risk comparable to that of young patients with IDDM

A Sound Approach to Language Matters: In Honor of Ocke-Schwen Bohn

The contributions in this Festschrift were written by Ocke’s current and former PhD-students, colleagues and research collaborators. The Festschrift is divided into six sections, moving from the smallest building blocks of language, through gradually expanding objects of linguistic inquiry to the highest levels of description - all of which have formed a part of Ocke’s career, in connection with his teaching and/or his academic productions: “Segments”, “Perception of Accent”, “Between Sounds and Graphemes”, “Prosody”, “Morphology and Syntax” and “Second Language Acquisition”. Each one of these illustrates a sound approach to language matters