2,194 research outputs found
Brief reports: anticipating the consequences of action: an fMRI study of intention-based task preparation
A key component of task preparation may be to anticipate the consequences of task-appropriate actions. This task switching study examined whether such type of "intentional" preparatory control relies on the presentation of explicit action effects. Preparatory BOLD activation in a condition with task-specific motion effect feedback was compared to identical task conditions with accuracy feedback only. Switch-related activation was found selectively in the effect feedback condition in the middle mid-frontal gyrus and in the anterior intraparietal sulcus. Consistent with research on attentional control, the posterior superior parietal lobule exhibited switch-related preparatory activation irrespective of feedback type. To conclude, preparatory control can occur via complementary attentional and intentional neural mechanisms depending on whether meaningful task-specific action effects lead to the formation of explicit effect representations
Visual Analysis of Spatio-Temporal Event Predictions: Investigating the Spread Dynamics of Invasive Species
Invasive species are a major cause of ecological damage and commercial
losses. A current problem spreading in North America and Europe is the vinegar
fly Drosophila suzukii. Unlike other Drosophila, it infests non-rotting and
healthy fruits and is therefore of concern to fruit growers, such as vintners.
Consequently, large amounts of data about infestations have been collected in
recent years. However, there is a lack of interactive methods to investigate
this data. We employ ensemble-based classification to predict areas susceptible
to infestation by D. suzukii and bring them into a spatio-temporal context
using maps and glyph-based visualizations. Following the information-seeking
mantra, we provide a visual analysis system Drosophigator for spatio-temporal
event prediction, enabling the investigation of the spread dynamics of invasive
species. We demonstrate the usefulness of this approach in two use cases
Ein Konzept zur numerischen Berechnung inkompressibler Strömungen auf Grundlage einer diskontinuierlichen Galerkin-Methode in Verbindung mit nichtüberlappender Gebietszerlegung
A new combination of techniques for the numerical computation of incompressible flow is presented. The temporal discretization bases on the discontinuous Galerkin-formulation. Both constant (DG(0)) and linear approximation (DG(1)) in time is discussed. In case of DG(1) an iterative method reduces the problem to a sequence of problems each with the dimension of the DG(0) approach. For the semi-discrete problems a Galerkin/least-squares method is applied. Furthermore a non-overlapping domain decomposition method can be used for a parallelized computation. The main advantage of this approach is the low amount of information which must be exchanged between the subdomains. Due to the slight bandwidth a workstation-cluster is a suitable platform. Otherwise this method is efficient only for a small number of subdomains. The interface condition is of the Robin/Robin-type and for the Navier-Stokes equation a formulation introducing a further pressure interface condition is used. Additionally a suggestion for the implementation of the standard k-epsilon turbulence model with special wall function is done in this context. All the features mentioned above are implemented in a code called ParallelNS. Using this code the verification of this approach was done on a large number of examples ranging from simple advection-diffusion problems to turbulent convection in a closed cavity
Challenging the nation-state from within: the emergence of transmunicipal solidarity in the course of the EU refugee controversy
In the context of the so-called refugee crisis, political disputes about solidarity become a central issue with member states applying competing concepts. At the same time, European cities use transnational networks to implement a new form of solidarity among municipalities via city diplomacy (Acuto, Morissette & Tsouros, 2017). Analyzing the deadlock between member states and the emerging activities of cities, we scrutinize the limits of existing approaches to political solidarity (e.g., Agustín & Jørgensen, 2019; Knodt, Tews & Piefer, 2014; Sangiovanni, 2013) to explain this phenomenon. Based on expert interviews and document analysis from a study on transnational municipal networks, we identify an emerging concept of solidarity that challenges the nation states as core providers of solidarity from within: transmunicipal solidarity focuses on joint action of local governments to scale out and scale up
Wirtschaftliche Generierung von Belieferungssimulationen unter Verwendung rechnerunterstützter Plausibilisierungsmethoden für die Bewertung der Eingangsdaten
The concept of the Digital-Factory provides a “single source of truth” Planning-System. This
establishes a possibility to generate intra-logistic-simulations with validated input data through a
standardized method. Therefore we have to take a closer look on input-data and its quality in
order to understand its way back through all the IT-systems to the point of birth.
This dissertation provides an approach how to validate this input-data with different,
independent methods, not only double-checking whether the information is complete but also
giving an answer to the question: is this data correct? Those methods will be combined in a
quality module in the Digital-Factory-Planning-System, showing inconsistencies which should
be inspected. The objective is collecting all necessary input-data in the required quality in order
to semi-automatic-generate a reliable simulation model in intra-logistics, avoiding costly
iterations or even wrong conclusions.Das Konzept der Digitalen Fabrik bietet die Möglichkeit, ein Planungssystem mit einer einheitlichen Datengrundlage aufzubauen. Dies schafft die Voraussetzungen, um Belieferungssimulationen mit plausibilisierten Eingangsdaten weitestgehend automatisiert generieren zu können. Die Eingangsdaten sind der Schlüssel zum Erfolg. Nur wer in gewachsenen IT-Landschaften mit unzähligen Schnittstellen Transparenz schaffen kann, weiß, woher welche Daten kommen und wie diese erhoben werden, kann damit auch die Qualität der Eingangsdaten – und dadurch auch die Qualität der Simulationsergebnisse beurteilen.
Diese Dissertation möchte einen Beitrag leisten, wie diese Eingangsdaten mit unterschiedlichen, unabhängigen Methoden untersucht werden können. Es sollen nicht nur Fragen zur Vollständigkeit der Eingangsdaten beantwortet werden, sondern vielmehr Antworten gegeben werden, ob die Eingangsdaten korrekt sind. Es wird aufgezeigt, wie diese Methoden im Umfeld der Digitalen Fabrik zentral in einem Simulationsgerüst gebündelt werden können, um eine einheitliche Plattform zur Plausibilisierung zu schaffen. Darauf aufbauend können diese plausibilisierten Daten verwendet werden, um eine Belieferungssimulation aufzubauen. Dies spart nicht nur Zeit, sondern kann auch falsche Schlussfolgerungen auf Basis fehlerhafter Eingangsdaten verhindern
ETHTID: Deployable Threshold Information Disclosure on Ethereum
We address the Threshold Information Disclosure (TID) problem on Ethereum: An arbitrary number of users commit to the scheduled disclosure of their individual messages recorded on the Ethereum blockchain if and only if all such messages are disclosed. Before a disclosure, only the original sender of each message should know its contents. To accomplish this, we task a small council with executing a distributed generation and threshold sharing of an asymmetric key pair. The public key can be used to encrypt messages which only become readable once the threshold-shared decryption key is reconstructed at a predefined point in time and recorded on-chain. With blockchains like Ethereum, it is possible to coordinate such procedures and attach economic stakes to the actions of participating individuals. In this paper, we present ETHTID, an Ethereum smart contract application to coordinate Threshold Information Disclosure. We base our implementation on ETHDKG [1], a smart contract application for distributed key generation and threshold sharing, and adapt it to fit our differing use case as well as add functionality to oversee a scheduled reconstruction of the decryption key. For our main cost saving optimisation, we show that the security of the underlying cryptographic scheme is maintained. We evaluate how the execution costs depend on the size of the council and the threshold and show that the presented protocol is deployable on Ethereum with a council of more than 200 members with gas savings of 20--40\% compared to ETHDKG
ETHTID: Deployable Threshold Information Disclosure on Ethereum
We address the Threshold Information Disclosure (TID) problem on Ethereum: An
arbitrary number of users commit to the scheduled disclosure of their
individual messages recorded on the Ethereum blockchain if and only if all such
messages are disclosed. Before a disclosure, only the original sender of each
message should know its contents. To accomplish this, we task a small council
with executing a distributed generation and threshold sharing of an asymmetric
key pair. The public key can be used to encrypt messages which only become
readable once the threshold-shared decryption key is reconstructed at a
predefined point in time and recorded on-chain. With blockchains like Ethereum,
it is possible to coordinate such procedures and attach economic stakes to the
actions of participating individuals. In this paper, we present ETHTID, an
Ethereum smart contract application to coordinate Threshold Information
Disclosure. We base our implementation on ETHDKG [1], a smart contract
application for distributed key generation and threshold sharing, and adapt it
to fit our differing use case as well as add functionality to oversee a
scheduled reconstruction of the decryption key. For our main cost saving
optimisation, we show that the security of the underlying cryptographic scheme
is maintained. We evaluate how the execution costs depend on the size of the
council and the threshold and show that the presented protocol is deployable on
Ethereum with a council of more than 200 members with gas savings of 20-40%
compared to ETHDKG
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