Repetition probability effects for inverted faces

It has been shown, that the repetition related reduction of the blood-oxygen level dependent (BOLD) signal is modulated by the probability of repetitions (P(rep)) for faces (Summerfield et al., 2008), providing support for the predictive coding (PC) model of visual perception (Rao and Ballard, 1999). However, the stage of face processing where repetition suppression (RS) is modulated by P(rep) is still unclear. Face inversion is known to interrupt higher level configural/holistic face processing steps and if modulation of RS by P(rep) takes place at these stages of face processing, P(rep) effects are expected to be reduced for inverted when compared to upright faces. Therefore, here we aimed at investigating whether P(rep) effects on RS observed for face stimuli originate at the higher-level configural/holistic stages of face processing by comparing these effects for upright and inverted faces. Similarly to previous studies, we manipulated P(rep) for pairs of stimuli in individual blocks of fMRI recordings. This manipulation significantly influenced repetition suppression in the posterior FFA, the OFA and the LO, independently of stimulus orientation. Our results thus reveal that RS in the ventral visual stream is modulated by P(rep) even in the case of face inversion and hence strongly compromised configural/holistic face processing. An additional whole-brain analysis could not identify any areas where the modulatory effect of probability was orientation specific either. These findings imply that P(rep) effects on RS might originate from the earlier stages of face processing. © 2014 Elsevier Inc

Building Digital Trust to Protect Whistleblowers - A blockchain-based Reporting Channel

Organizations today need internal reporting channels to report illegal/unethical misconduct. For this purpose, organizations set up one or more - often digital - internal reporting channels. Persons/Employees who want to report misconduct, so-called whistleblowers, expose themselves to reprisals and therefore need trustworthy reporting channels which ensure ´Digital Trust´. Blockchain, a technology that overcomes the need for trust due to its properties of immutability and integrity of data, could be promising as underlying technology for a digital reporting channel which is recognized as trustworthy. In our research, we explored multiple perspectives relevant to a trustworthy digital reporting system. Applying design science research, we evaluated the current state of the art of (digital) reporting channels and developed a prototypical blockchain-based reporting solution called “Integrity@Inside”. The prototype is being iteratively demonstrated and pre-evaluated

An empirical investigation of the benefit of increasing the temporal resolution of task-evoked fMRI data with multi-band imaging

Objective There is a tendency for reducing TR in MRI experiments with multi-band imaging. We empirically investigate its benefit for the group-level statistical outcome in task-evoked fMRI. Methods Three visual fMRI data sets were collected from 17 healthy adult participants. Multi-band acquisition helped vary the TR (2000/1000/410 ms, respectively). Because these data sets capture different temporal aspects of the haemodynamic response (HRF), we tested several HRF models. We computed a composite descriptive statistic, H, from β’s of each first-level model fit and carried it to the group-level analysis. The number of activated voxels and the t value of the group-level analysis as well as a goodness-of-fit measure were used as surrogate markers of data quality for comparison. Results Increasing the temporal sampling rate did not provide a universal improvement in the group-level statistical outcome. Rather, both the voxel-wise and ROI-averaged group-level results varied widely with anatomical location, choice of HRF and the setting of the TR. Correspondingly, the goodness-of-fit of HRFs became worse with increasing the sampling frequency. Conclusion Rather than universally increasing the temporal sampling rate in cognitive fMRI experiments, these results advocate the performance of a pilot study for the specific ROIs of interest to identify the appropriate temporal sampling rate for the acquisition and the correspondingly suitable HRF for the analysis of the data

Fourier-Splitting Method for Solving Hyperbolic LQR Problems

We consider the numerical approximation to linear quadratic regulator problems for hyperbolic partial differential equations where the dynamics is driven by a strongly continuous semigroup. The optimal control is given in feedback form in terms of Riccati operator equations. The computational cost relies on solving the associated Riccati equation and computing the optimal state. In this paper we propose a novel approach based on operator splitting idea combined with Fourier’s method to efficiently compute the optimal state. The Fourier’s method allows to accurately approximate the exact flow making our approach computational efficient. Numerical experiments in one and two dimensions show the performance of the proposed method

RePlay-DH - Realisierung einer Plattform und begleitender Dienste zum Forschungsdatenmanagement für die Fachcommunity - Digital Humanities

Das Projekt RePlay-DH hat zum Ziel, ein Werkzeug zu entwickeln, das die Wissenschaftler bereits im Forschungsprozess bei der nachhaltigen Dokumentation und Archivierung der Forschungsdaten unterstützt. Das zentrale Element dabei ist der „RePlay-Gedanke“: Wiederauffindbarkeit und Reproduktion von Forschungsergebnissen. Um praxisnahe Lösungen zu schaffen, analysiert das Projekt hierfür exemplarisch Workflows aus der Computerlinguistik. Zwar kommen die Wissenschaftler in den digitalen Geisteswissenschaften oft sehr gut an die benötigten Werkzeuge und Eingabedaten, die Forschungsprozesse selbst werden jedoch häufig nur skizzenhaft dokumentiert. Mit RePlay-DH soll eine Möglichkeit geschaffen werden, den Arbeitsprozess der Forscher mit einem geringen Mehraufwand zu dokumentieren und für Dritte nachvollziehbar zu machen. Dazu wird ein Java-Client entwickelt, der mit Hilfe von einfachen Versionierungswerkzeugen den Dokumentationsworkflow der Forschenden gezielt unterstützt. In komplexen Projekten soll dieses Vorgehen dabei helfen, verschiedene Optionen während des Forschungsprozesses auszuloten und zu dokumentieren. Dabei bleibt es stets den Wissenschaftlern überlassen, welche Teile des eigenen Projekts archiviert, mit Kollegen geteilt oder veröffentlicht werden sollen

Circular economy for durable products and materials : the recycling of plastic building products in Germany ; status quo, potentials and recommendations

The construction sector is the second largest area for the application for plastics. Due to the long life times of construction products, the implementation of the circular economy faces its own challenges. To investigate this challenge, the study covers a market study for Germany, voluntary take-back and recycling schemes of construction products, as well as the use of plastic recyclates in construction products. In addition, plastic packaging of construction products is covered. Opportunities and barriers to the use of recycled plastics in construction products are derived from the intersection of available technologies, recyclate supply, and technical requirements for construction products. The report concludes with recommendations to various stakeholders on how to promote the use of recyclates in construction products and their packaging. Important points here are the introduction of a recyclate quota for films as construction product packaging and the description of recycling possibilities and recyclate content in the technical documentation of construction products