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Online publication system of Friedrich-Alexander-Universität Erlangen-Nürnberg

The online publication system OPEN FAU is the central publication platform for Open Access publishing for all members of Friedrich-Alexander-Universität. Qualified works from research and teaching may be published here free of charge, either as a primary or secondary publication. The full texts are permanently available worldwide and are findable and citable via catalogues and search engines.

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Recent Submissions

Conference object
Transfer Learning for Predictive Process Monitoring
(2024-06) Liessmann, Annina; Wang, Weixin; Weinzierl, Sven; Zilker, Sandra; Matzner, Martin
Event log data reflects the behavior of business processes that are mapped in organizational information systems. Predictive process monitoring (PPM) transforms this data into value; it creates process-related predictions to provide insights required for proactive interventions at process runtime. Existing PPM techniques require sufficient amounts of event data or other relevant resources that might not be readily available, preventing some organizations from taking advantage of PPM. In this paper, we present a transfer-learning-based technique for PM, allowing organizations without suitable data or other relevant resources to implement PPM for effective decision support. We instantiate our artifact, and apply and evaluate it on a real-life use case. The use case includes two event logs for purchase-to-pay processes of two organizations. Our results provide evidence that knowledge of a process of one organization can be transferred to a similar process of another organization to enable PPM in the target organization.
HyperLeech: Stealthy System Analysis with Minimal Target Impact through DMA-Based Hypervisor Injection
Technical reports / Department Informatik : CS-2024-01, (2024) Palutke, Ralph; Ruderich, Simon; Wild, Matthias; Hacker, Jonathan; Konrad, Jonas; Freiling, Felix
In the recent past, malware began incorporating anti-forensic techniques at the kernel level to hinder analysts from gaining meaningful insights. Consequently, methods that allow the stealthy analysis of a system have become increasingly important. Recent approaches often rely on external devices that use Direct Memory Access (DMA) to transparently analyze volatile memory or shift a running system into a Virtual Machine (VM), performing forensics from the hypervisor level. While DMA suffers from low atomicity and a lack of semantics, virtualizing a running system usually requires privileged credentials and the installation of a kernel driver, which considerably alters a target’s state. In this report, we present HyperLeech, the first approach which uses DMA to stealthily inject a forensic hypervisor into the memory of a running target host, transparently shifting its operation into a hardware-accelerated VM. For injecting code minimally invasively, we use external PCILeech hardware to enable DMA to the target memory. Combining the advantages of hardware-supported virtualization with the benefits provided by DMA-based code injection, our approach can serve analysts as a stealthy and privileged execution layer that enables powerful live forensics and atomic memory snapshots without the risk of destroying evidence or alerting malware. Our experiments reveal that HyperLeech is sufficient for virtualizing modern multi-core hosts during runtime while neither causing a notable impact on the target’s processor and memory state nor introducing a significant performance overhead. To give the target the impression of possessing the entire available memory even after injecting our system, HyperLeech incorporates a sophisticated DMA-based memory swapping protocol that makes the content evicted by our hypervisor re-available upon request. Although HyperLeech might be misused for malicious purposes, we conclude that it provides new possibilities for stealthy system analysis and digital forensics, raising the bar for malware to evade detection.
Doctoral thesis
Highly Reactive Aluminyl Anions and Monomeric Alumoxanes
(2024) Grams, Samuel; Harder, Sjoerd
Dissertationsschrift zur Erlangung des Doktorgrades Dr. rer. nat.
Doctoral thesis
(2024) Ghadiriasli, Rahil; Büttner, Andrea
The living tree and its obtained wood have played a prominent role in human everyday life in the form of building material and furniture, or in products of daily use. The aroma components emanating from wood-based products have a powerful influence on human Psychophysiological activity and have been used for mental, spiritual and physical healing. The wood aroma can be used in the indoor environment to foster relaxation and stress release effects. The current study was conducted to determine the individual wood odor and its constituents in two diverse types of woods, namely Oak wood and cembran pine wood. Oak wood has been used since long during the maturation and aging process imparting aroma and flavor in alcoholic beverages and vinegar as by-products that have been either fermented or aged in oak barrels. Several investigations targeted the aroma composition of modified and heat-treated oak wood, but only little information about aroma-active compounds constituting the native and raw oak wood is available. The Cembran pine wood (Pinus cembra L.), also known as Arolla pine, Swiss pine, or Stone pine, has a prominent and long-lasting aroma that has been reported to relieve stress and that is widely used in aromatherapy. However, the odorants responsible for this distinctive aroma are not yet comprehensively revealed. Therefore, the main objective of this thesis was to characterize the impacting odorants and to deepen the knowledge about native oak wood and unique Cembran pine wood odor by applying a combinatory chemo-analytical approach based on human-sensory evaluations and multi-dimensional gas chromatographic and mass spectrometric techniques. Furthermore, it was tried in this thesis to gain deeper insights into formation pathways and odor sources in these two types of wood and their applications. Most of these odorants comprised aldehydes, acids, lactones, a series of terpenes, mostly mono- and sesquiterpenes, and several odor-active compounds containing a phenolic core moiety. The odor profiles of all wood samples were compared, the potent odorants were determined, and selected odorants of both types of wood samples (oak and Cembran wood samples) were quantified by application of stable isotope dilution assays (SIDA). Odor activity values (OAVs) were calculated based on the odor threshold (OTs) determined in water. The second part of this thesis dealt with the investigation of the effects of different geographical regions and pedoclimatic conditions on the odor of different wood samples. This study focused on elucidating the smell profiles of several natural oak samples from Germany, Austria, and Hungary. Particular consideration is given to view the current challenges associated with climate change on the forestry sector, and thus concerning the respective regional conditions, and underwent statistical interpretation. In the case of Cembran wood, the influence of different geographical forest regions in Austria and Italy was determined and evaluated by means of principal component analysis (PCA) and statistical interpretation of obtained data. Recombination experiments by mixing the dominant odor-active compounds in their naturally occurring concentrations revealed a good agreement of the model mixtures with the overall smell of the respective native wood samples. In addition, the structure odor relationships in representative substance classes of wood were elucidated. Specifically, the smell impressions of guaiacol and selected structurally related odorants such as alkylated, alkenylated, methoxylated and halogenated guaiacol derivatives were studied. All investigated compounds elicited characteristic smoky, vanilla-like, and /or clove-like smell impressions. Smoky smells, primarily comprising guaiacols, phenols and cresols, are enjoyed in diverse foods and beverages such as wine, whiskey, smoked ham, cheese, or baked goods such as pizza. Furthermore, the studies indicated that the odor properties of alkylated and halogenated guaiacols and phenols demonstrated the smoky smells are not the same for everyone and can be differently perceived in individual humans. Overall, the odor threshold investigation of guaiacol and its alkylated, alkenylated, and methoxylated derivatives showed that no specific substituent caused a significant and universal effect on OT. However, the positioning of the substituents to the hydroxyl function seems to have an impact on OT. Obtained data could be used to identification and analysis of the investigated compounds. Furthermore, the results can also be avail in understanding the structure and the odor correlation of compounds, which is still not fully resolved. Finally, to investigate the wine off-odors, barrel-aged wine samples were analyzed by gas chromatography-olfactometry (GC-O), with regards to the presence of the typical earthy-smelling off-odor. The 2-methylisoborneol (2-MIB) was detected in these wines, although the wine samples were seven years old and all the previous studies showed that this substance is unstable in wine and must. Degradation products of 2-MIB were synthesised, and with regard to their odor, these dehydration products were found to be odorless. To investigate this paradoxical situation, 2-MIB stability was analyzed in wine and model solutions, starting with an elevated initial concentration. Therefore it was concluded that although 2-MIB concentration greatly decreased with time it still can be detected in old wines and can induce the earthy off-odor.
Doctoral thesis
With all, for all: From context-sensitive physical activity assessment to population-based physical activity promotion with a focus on health equity
(2024) Kohler, Simone; Pfeifer, Klaus
For decades, the epidemiology of physical activity (PA) and PA-related health promotion has been concerned with the problem of physical inactivity and has pursued a common goal: a healthier population through more PA. While epidemiology focuses on risk and protective factors for diseases, health promotion focuses on health promoting factors, health resources, and health equity. The latter is so important because non-communicable diseases (NCDs) follow a social gradient, affecting people with social disadvantages more than advantaged ones. One of the main risk factors for NCDs is physical inactivity. Between 2020 and 2030, nearly 500 million people will suffer from NCDs due to physical inactivity. Addressing this issue urgently remains a major challenge for all stakeholders involved in reducing health inequities through PArelated health promotion, whether they are researchers, policy-makers or local authorities. The first part of this dissertation is located in the field of epidemiology of PA. The development and evaluation of a computer based PA recall (cpar24) for recording PA and its meaning for the epidemiology of physical activity, as well as the relevance of context-sensitive data, are the focus. The evaluation results of cpar24 showed that it is a user-friendly, practical, valid, and reliable method for assessing activity data of German adults. The cpar24 is not only suitable for monitoring PA but also for assessing contextual determinants (type and domain), which enables a better understanding of health effects. Furthermore, insights can be derived from the cpar24 data, which serve as a basis for the development of specific recommendations for promoting PA. If it is possible to measure the PA behavior of population groups with different social status in representative cohort studies, this can also provide urgently needed information for improving health equity. The second part of this work deals with PA-related health promotion. One of the primary objectives was to create an umbrella review of successful population-based approaches to promoting PA, with a particular focus on health equity, to update the National Recommendations for PA and PA Promotion in Germany published in 2016. A total of six review articles were identified between January 2015 and December 2021, which represents an increase in scientific publications in this field compared to previous years, which included only two review articles. However, the state of research and thus the availability of scientific evidence on the effectiveness of population-based measures to promote PA with a focus on health equity is limited. In addition to the complexity of these approaches in complex systems such as communities, challenges for evaluation such as inadequate theoretical foundation and missing quality criteria are also discussed. In another study, the question of how to sustainably implement structure-building community-based PA-related health promotion with a focus on health equity in Germany was investigated. After several iterations and collaboration processes, a sixstage action model for successful and sustainable implementation of PA-related health promotion with a focus on health equity in the community was adopted in collaboration with stakeholders from science, politics, and local practice. Furthermore, this approach was systematically analyzed and theoretically reflected on the basis of a “conceptual model of the transdisciplinary research process”. Overall, it was confirmed that new knowledge could be generated for both practice and science by taking into account scientific and societal knowledge through several reflection loops. The subtitle of this work, “with all, for all”, emphasizes with “for all” the need to reach all people in future public health efforts, especially those population groups whose chances are limited by social disadvantage. “With all” emphasizes that “all stakeholders”, i.e. from science (epidemiology together with health promotion), politics, and practice, must be involved and work together to achieve sustainable effects on public health. In summary, the results presented here from two different research perspectives provide a deeper insight into existing challenges and show equitable solutions for reducing physical inactivity. The discussed interconnections between the epidemiology of PA and PA-related health promotion illustrate the importance of their collaboration, especially when epidemiological findings are (or can be) used in health promotion practice in such a way that sustainable interventions reach all population groups and contribute to improving the health of the population in an equitable manner.