The Low Frequency Array (LOFAR) radio telescope is an international aperture synthesis radio telescope used to study the Universe at low frequencies. One of the goals of the LOFAR telescope is to... Show moreThe Low Frequency Array (LOFAR) radio telescope is an international aperture synthesis radio telescope used to study the Universe at low frequencies. One of the goals of the LOFAR telescope is to conduct deep wide-field surveys. Here we will discuss a framework for the processing of the LOFAR Two Meter Sky Survey (LoTSS). This survey will produce close to 50 PB of data within five years. These data rates require processing at locations with high-speed access to the archived data. To complete the LoTSS project, the processing software needs to be made portable and moved to clusters with a high bandwidth connection to the data archive. This work presents a framework that makes the LOFAR software portable, and is used to scale out LOFAR data reduction. Previous work was successful in pre-processing LOFAR data on a cluster of isolated nodes. This framework builds upon it and and is currently operational. It is designed to be portable, scalable, automated and general. This paper describes its design and high level operation and the initial results processing LoTSS data. Show less
The aim of evolutionary level set approximation is to find a finite representation of a level set of a given black box function. The problem of level set approximation plays a vital role in solving... Show moreThe aim of evolutionary level set approximation is to find a finite representation of a level set of a given black box function. The problem of level set approximation plays a vital role in solving problems, for instance in fault detection in water distribution systems, engineering design, parameter identification in gene regulatory networks, and in drug discovery. The goal is to create algorithms that quickly converge to feasible solutions and then achieve a good coverage of the level set. The population based search scheme of evolutionary algorithms makes this type of algorithms well suited to target such problems. In this paper, the focus is on continuous black box functions and we propose a challenging benchmark for this problem domain and propose dual mutation strategies, that balance between global exploration and local refinement. Moreover, the article investigates the role of different indicators for measuring the coverage of the level set approximation. The results are promising and show that even for difficult problems in moderate dimension the proposed evolutionary level set approximation algorithm (ELSA) can serve as a versatile and robust meta-heuristic. Show less
We propose a novel classification method that integrates into existing agile software development practices by collecting data records generated by software and tools used in the development... Show moreWe propose a novel classification method that integrates into existing agile software development practices by collecting data records generated by software and tools used in the development process. We extract features from the collected data and create visualizations that provide insights, and feed the data into a prediction framework consisting of a deep neural network. The features and results are validated against conceptual frameworks that model the development methodologies as similar processes in other contexts. Initial results show that the visualization and prediction techniques provide promising outcomes that may help development teams and management gain better understanding of past events and future risks. Show less
The nation state is discovering the limits of its crisis management capacities. Events such as Ebola and Zika, the downing of flight MH17 over the Ukraine, sinking ships with refugees, cyber... Show moreThe nation state is discovering the limits of its crisis management capacities. Events such as Ebola and Zika, the downing of flight MH17 over the Ukraine, sinking ships with refugees, cyber attacks and urban terrorism serve as reminders that crises faced at home often originate in far-away and unsuspected domains. As the transboundary dimensions of many crises and disasters increasingly manifest themselves, the need for international cooperation appears ever clearer. But it does not always happen, even in the European Union. This prompts our question: Why do EU member states elect to cooperate in response to some transboundary crises and not to others? We bring together the crisis and collective action literature to formulate a theoretical framework that can help to answer these questions. Show less
There does not appear to be consensus on how to optimally match students during the peer feedback phase: with same-ability or different-ability peers. The current study explored this issue in the... Show moreThere does not appear to be consensus on how to optimally match students during the peer feedback phase: with same-ability or different-ability peers. The current study explored this issue in the context of an academic writing task. Adopting a quasi-experimental design, 94 undergraduate students provided anonymous peer feedback on each other’s draft essays. The relations between students’ ability match, feedback quality, and writing performance were investigated. Surprisingly, neither individual ability nor students’ ability match directly related to writing performance, and feedback quality did not depend on students’ ability match. Also, peer feedback quality was not related to writing performance, and authors of varying ability levels benefited to a similar extent from peer feedback on different aspects of the text. Show less
Parra, C.; Rohaut, C.; Maeckelbergh, M.; Issarny, V.; Holston, J. 2017
This paper analyzes existing practices and supporting technologies for Participatory Budgeting (PB), with a special focus on US-related initiatives, as a mean to understand the current and future... Show moreThis paper analyzes existing practices and supporting technologies for Participatory Budgeting (PB), with a special focus on US-related initiatives, as a mean to understand the current and future design space of ICT for participatory democracy. We suggest new design opportunities for ICT to facilitate citizen collaboration in the PB process, and by extension, to reflect on how these technologies could better foster deliberative decision-making at a scale that is both small and large. Show less
