Tuning and optimization for a variety of many-core architectures without changing a single line of implementation code using the Alpaka library

We present an analysis on optimizing performance of a single C++11 source code using the Alpaka hardware abstraction library. For this we use the general matrix multiplication (GEMM) algorithm in order to show that compilers can optimize Alpaka code effectively when tuning key parameters of the algorithm. We do not intend to rival existing, highly optimized DGEMM versions, but merely choose this example to prove that Alpaka allows for platform-specific tuning with a single source code. In addition we analyze the optimization potential available with vendor-specific compilers when confronted with the heavily templated abstractions of Alpaka. We specifically test the code for bleeding edge architectures such as Nvidia's Tesla P100, Intel's Knights Landing (KNL) and Haswell architecture as well as IBM's Power8 system. On some of these we are able to reach almost 50\% of the peak floating point operation performance using the aforementioned means. When adding compiler-specific #pragmas we are able to reach 5 TFLOPS/s on a P100 and over 1 TFLOPS/s on a KNL system.Comment: Accepted paper for the P\^{}3MA workshop at the ISC 2017 in Frankfur

Parents’ and Children’s Implicit Theories About Ability: How and Under What Circumstances They Relate to Different Aspects of Children’s Academic Success

Children’s and parents’ implicit theories (ITs) about whether abilities are fixed or malleable predict various learning-related behaviors and different aspects of children’s academic success. For children’s ITs, however, it has not yet been adequately investigated whether they predict learning strategy use, which is related to academic success. Thus, Study 1 examined if children’s ITs predict (a) their use of cognitive and metacognitive strategies and (b) how much use they make of an intervention that teaches such strategies. As for parents’ ITs, their effects on children’s academic success and mediating mechanisms are not well researched. Given the mixed results in this area, researchers suggested that parents’ ITs might be most relevant in situations that make children’s intellectual potential salient, such as during educational transitions. Thus, Studies 2 and 3 examined the effects of parents’ ITs in such a situation, namely in grade four of Bavarian primary school, where it is decided whether children will attend a Gymnasium. Study 2 examined if parents’ ITs predict their children’s academic achievement and whether this relationship is mediated by (a) children’s ITs and (b) parents’ learning-related behaviors. Study 3 examined if parents’ ITs predict whether (a) children achieve the grade average required for attending a Gymnasium and (b) parents actually send their children to a Gymnasium (given that they have achieved the required grade average). It also examined whether (c) parents’ ITs play a greater role when children just barely achieve the required grade average

Do Implicit Theories About Ability Predict Self-Reports and Behavior-Proximal Measures of Primary School Students’ In-Class Cognitive and Metacognitive Learning Strategy Use?

Although studies show relations between implicit theories about ability (ITs) and cognitive as well as metacognitive learning strategy use, existing studies suffer from an overreliance on broad-brush self-report measures of strategy use and limited ecological validity. Moreover, studies rarely examine younger students, and research on ITs and how much students benefit from interventions on learning strategies is lacking. Therefore, we investigated in ecologically valid settings (regular classroom instruction) whether primary school students’ ITs are related to their use of cognitive strategies (text reduction strategies based on identifying a text’s main ideas) and metacognitive strategies, assessed with (a) typical self-report scales and (b) more behavior-proximal measures. We also investigated whether students’ ITs predict how much they benefit from a previously evaluated 4-week intervention on cognitive and metacognitive strategies during regular classroom instruction (i.e., how much self-report scales and behavior-proximal measures for strategy use increase over the course of the intervention). Participants were 436 German primary school students (third and fourth graders). The data were analyzed using mixed linear regression analyses. Strength of students’ incremental theory was positively related to metacognitive strategy use, but not cognitive strategy use, when measured with self-report scales. For behavior-proximal measures, strength of incremental theory was positively related to the effectiveness of students’ cognitive strategy use and their extent of strategy monitoring (one of the two metacognitive strategies examined), but not to the quality of their goal setting (the second metacognitive strategy). Unexpectedly, students with a stronger incremental theory did not benefit more from the intervention

Implizite Theorien von Eltern und deren Zusammenhänge mit elterlichem lernbezogenen Verhalten sowie den impliziten Theorien und dem Lern- und Leistungsverhalten ihrer Kinder: Ein Literaturüberblick

Während implizite Theorien (auch bekannt als Mindsets) von Lernenden sowie deren Zusammenhänge mit Lern- und Leistungsverhalten sehr umfassend untersucht wurden, gibt es nur wenige Studien zu impliziten Theorien von Eltern und deren Zusammenhängen mit elterlichem lernbezogenen Verhalten sowie den impliziten Theorien und dem Lern- und Leistungsverhalten ihrer Kinder. Zudem ist wenig über die genauen Wirkmechanismen bekannt sowie über die Bedingungen, unter denen elterliche implizite Theorien elterliches Verhalten vorhersagen. Der vorliegende Beitrag gibt einen systematischen Überblick über Studien zu diesen Themen. Hierfür wurde in verschiedenen Datenbanken eine systematische Literaturrecherche nach relevanten Artikeln aus Fachzeitschriften durchgeführt, die zwischen 1990 und 2021 veröffentlicht worden waren. Bei dieser Recherche konnten insgesamt 11 passende Artikel identifiziert werden, deren Befunde gegliedert nach den untersuchten Bereichen dargestellt werden. Neben Befunden zu elterlichen impliziten Theorien und ihren Zusammenhängen mit deren lernbezogenem Verhalten sowie den impliziten Theorien und dem Lern- und Leistungsverhalten ihrer Kinder werden vermittelnde Mechanismen diskutiert und es wird thematisiert, unter welchen Rahmenbedingungen implizite Theorien von Eltern besonders relevant erscheinen. Basierend darauf werden Forschungslücken aufgezeigt und theoretische und praktische Implikationen herausgearbeitet

Time Moves Faster When There is Nothing You Anticipate: The Role of Time in MEV Rewards

We present a novel analysis of a competitive dynamic present on Ethereum known as "waiting games", where validators can use their distinct monopoly position in their assigned slots to delay block proposals in order to optimize returns through Maximal Extractable Value (MEV) payments, a type of incentive outside the Proof-of-Stake incentive scheme. However, this strategy risks block exclusion due to missed slots or potential orphaning. Our analysis reveals evidence that, although there are substantial incentives to undertaking the risks, validators are not capitalizing on waiting games, leaving potential profits unrealized. Moreover, we present an agent-based model to test the eventual consensus disruption caused by waiting games under different settings, arguing that such disruption only occurs with significant delay strategies. Ultimately, this research provides in-depth insights into Ethereum's waiting games, illuminating the trade-offs and potential profit opportunities for validators in this evolving blockchain landscape

Responses of Arctic cyclones to biogeophysical feedbacks under future warming scenarios in a regional Earth system model

Arctic cyclones, as a prevalent feature in the coupled dynamics of the Arctic climate system, have large impacts on the atmospheric transport of heat and moisture and deformation and drifting of sea ice. Previous studies based on historical and future simulations with climate models suggest that Arctic cyclogenesis is affected by the Arctic amplification of global warming, for instance, a growing land-sea thermal contrast. We thus hypothesize that biogeophysical feedbacks (BF) over the land, here mainly referring to the albedo-induced warming in spring and evaporative cooling in summer, may have the potential to significantly change cyclone activity in the Arctic. Based on a regional Earth system model (RCA-GUESS) which couples a dynamic vegetation model and a regional atmospheric model and an algorithm of cyclone detection and tracking, this study assesses for the first time the impacts of BF on the characteristics of Arctic cyclones under three IPCC Representative Concentration Pathways scenarios (i.e. RCP2.6, RCP4.5 and RCP8.5). Our analysis focuses on the spring- and summertime periods, since previous studies showed BF are the most pronounced in these seasons. We find that BF induced by changes in surface heat fluxes lead to changes in land-sea thermal contrast and atmospheric stability. This, in turn, noticeably changes the atmospheric baroclinicity and, thus, leads to a change of cyclone activity in the Arctic, in particular to the increase of cyclone frequency over the Arctic Ocean in spring. This study highlights the importance of accounting for BF in the prediction of Arctic cyclones and the role of circulation in the Arctic regional Earth system

FlyATM4E (SESAR ER) - Mitigating aviation climate impact by climate-optimized aircraft trajectories

Darstellung des Projekts FlyATM4

A concept for multi-criteria environmental assessment of aircraft trajectories

Comprehensive assessment of the environmental aspects of flight movements is of increasing interest to the aviation sector as a potential input for developing sustainable aviation strategies that consider climate impact, air quality and noise issues simultaneously. However, comprehensive assessments of all three environmental aspects do not yet exist and are in particular not yet operational practice in flight planning. The purpose of this study is to present a methodology which allows to establish a multi-criteria environmental impact assessment directly in the flight planning process. The method expands a concept developed for climate optimisation of aircraft trajectories, by representing additionally air quality and noise impacts as additional criteria or dimensions, together with climate impact of aircraft trajectory. We present the mathematical framework for environmental assessment and optimisation of aircraft trajectories. In that context we present ideas on future implementation of such advanced meteorological services into air traffic management and trajectory planning by relying on environmental change functions (ECFs). These ECFs represent environmental impact due to changes in air quality, noise and climate impact. In a case study for Europe prototype ECFs are implemented and a performance assessment of aircraft trajectories is performed for a one-day traffic sample. For a single flight fuel-optimal versus climate-optimized trajectory solution is evaluated using prototypic ECFs and identifying mitigation potential. The ultimate goal of such a concept is to make available a comprehensive assessment framework for environmental performance of aircraft operations, by providing key performance indicators on climate impact, air quality and noise, as well as a tool for environmental optimisation of aircraft trajectories. This framework would allow studying and characterising changes in traffic flows due to environmental optimisation, as well as studying trade-offs between distinct strategic measure

Flying Air Traffic Management for the benefit of environment and climate

FlyATM4E developed a concept to identify climate-optimized aircraft trajectories which enable a robust and eco-efficient reduction in aviations climate impact expanding on approved climate-assessment methods and optimization approaches. Applying state of the art climate impact quantification methods for aircraft emissions, robust climate-optimized flight planning in trajectory-based operations is investigated