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Iris Braun

Publications and source records attributed to Iris Braun.

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Adaptive Learning Mechanisms for Learning Management Systems: A Scoping Review and Practical Considerations

Background: Traditional Learning Management Systems (LMS) usually offer a one-size-fits-all solution that cannot be customized to meet specific learner needs. To address this issue, adaptive learning mechanisms are integrated either by LMS-specific approaches into individual LMSs or by system-independent mechanisms into various existing LMSs to increase reusability. Objective: We conducted a systematic review of the literature addressing the following research questions. How are adaptive learning mechanisms integrated into LMSs system-independently? How are they provided, how are they specified, and on which database do they operate? A priori, we proposed three hypotheses. First, the focused adaptive learning mechanisms, rarely consider existing data. Second, they usually support a limited number of data processing mechanisms. Third, the users intended to provide them, are rarely given the ability to adapt how they work. Furthermore, to investigate the differences between system-independent and LMS-specific approaches, we also included the latter. Design: We used Scopus, Web of Science and Google Scholar for gray literature to identify 3370 papers published between 2003 and 2023 for screening, and conducted a snowball search. Results: We identified 61 relevant approaches and extracted eight variables for them through in-depth reading. The results support the proposed hypotheses. Conclusion: Based on the challenges raised by the proposed hypotheses with regard to the relevant user groups, we defined two future research directions - developing a conceptual model for the system-independent specification of adaptive learning mechanisms and a corresponding architecture for the provision, and supporting the authoring of these mechanisms by users with low technical expertise.

cs.CY

The SAP Cloud Infrastructure Dataset: A Reality Check of Scheduling and Placement of VMs in Cloud Computing

Allocating resources in a distributed environment is a fundamental challenge. In this paper, we analyze the scheduling and placement of virtual machines (VMs) in the cloud platform of SAP, the world's largest enterprise resource planning software vendor. Based on data from roughly 1,800 hypervisors and 48,000 VMs within a 30-day observation period, we highlight potential improvements for workload management. The data was measured through observability tooling that tracks resource usage and performance metrics across the entire infrastructure. In contrast to existing datasets, ours uniquely offers fine-grained time-series telemetry data of fully virtualized enterprise-level workloads from both long-running and memory-intensive SAP S/4HANA and diverse, general-purpose applications. Our key findings include several suboptimal scheduling situations, such as CPU resource contention exceeding 40%, CPU ready times of up to 220 seconds, significantly imbalanced compute hosts with a maximum CPU~utilization on intra-building block hosts of up to 99%, and overprovisioned CPU and memory resources resulting into over 80% of VMs using less than 70% of the provided resources. Bolstered by these findings, we derive requirements for the design and implementation of novel placement and scheduling algorithms and provide guidance to optimize resource allocations. We make the full dataset used in this study publicly available to enable data-driven evaluations of scheduling approaches for large-scale cloud infrastructures in future research.

cs.DC