SearcharxivSearch

arXiv subjects

Stephan Kraft

Publications and source records attributed to Stephan Kraft.

2 recordsLinked to original sources

Intelligent resource prediction for SAP HANA continuous integration build workloads

Large enterprises often operate extensive Continuous Integration (CI) pipelines on large, heterogeneous compute clusters, where conservative, statically defined resource requirements are used to ensure build reliability. This practice leads to substantial system memory over-allocation, reduced cluster utilization, and increased operational costs. In this paper, we motivate the need for intelligent resource prediction by analyzing over 300,000 historical build executions from a production CI environment with more than one thousand compute nodes. Our analysis shows that, on average, more than 60% of allocated system memory remains unused. We then compare multiple machine learning approaches for predicting build task memory usage, including classification-based methods and regression-based quantile prediction. Our final solution employs a LightGBM-XGBoost quantile regression ensemble optimized to minimize under-allocation while reducing over-provisioning. We integrate this solution into the production CI pipeline via a microservice-based orchestration layer, achieving average memory savings of approximately 36GB per build and reducing under-allocation rates to below 0.3% without negatively impacting build execution times.

cs.DC

Spectral and spatial shaping of laser-driven proton beams using a pulsed high-field magnet beamline

Intense laser-driven proton pulses, inherently broadband and highly divergent, pose a challenge to established beamline concepts on the path to application-adapted irradiation field formation, particularly for 3D. Here we experimentally show the successful implementation of a highly efficient (50% transmission) and tuneable dual pulsed solenoid setup to generate a homogeneous (8.5% uniformity laterally and in depth) volumetric dose distribution (cylindrical volume of 5 mm diameter and depth) at a single pulse dose of 0.7 Gy via multi-energy slice selection from the broad input spectrum. The experiments have been conducted at the Petawatt beam of the Dresden Laser Acceleration Source Draco and were aided by a predictive simulation model verified by proton transport studies. With the characterised beamline we investigated manipulation and matching of lateral and depth dose profiles to various desired applications and targets. Using a specifically adapted dose profile, we successfully performed first proof-of-concept laser-driven proton irradiation studies of volumetric in-vivo normal tissue (zebrafish embryos) and in-vitro tumour tissue (SAS spheroids) samples.

physics.acc-ph