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Wilhelm Hasselbring

Publications and source records attributed to Wilhelm Hasselbring.

At least 19 recordsLinked to original sources

Reinforcement Learning-Based Production Scheduling in an Industry-Based Coating Scenario Using the Digital Model Playground

Production scheduling in complex manufacturing environments is challenging when sequence-dependent setup times, stochastic disturbances, and due-date constraints must be addressed simultaneously. While reinforcement learning (RL) methods have shown promising results in research, most studies rely on simplified benchmark processes, limiting their industrial relevance. This paper demonstrates the applicability of RL-based scheduling in an industry-inspired coating process that reflects practical complexities such as sequence-dependent setup times, machine breakdowns, and variable utilization. The open-source Digital Model Playground (DMPG), a discrete event simulation framework, is used to model the scenario and to train RL agents. Two standard algorithms, Deep Q-Networks and Proximal Policy Optimization, are benchmarked against conventional dispatching rules to illustrate feasibility and to provide a transparent testbed for further research. Results indicate that RL-based scheduling achieves balanced improvements across key performance indicators, with PPO delivering the most robust performance. The main contribution of this work is to bridge the gap between academic research and industrial practice by validating RL-based scheduling in a realistic, shareable scenario and by providing a reusable open-source framework for future studies.

cs.AI

The PM-EdgeMap: Towards Real-Time Process Mining on the Edge-Cloud Continuum

Smart factories are evolving into Cyber-Physical Systems (CPS), demanding increased autonomy. This necessitates real-time decision making, facilitated by insights derived from sensor data. Process mining offers a valuable approach to gain such insights and guide actions. The edge computing paradigm supports this real-time requirement by enabling network communication between sensors and leveraging nearby computing resources. This paper investigates the implications of performing real-time process mining algorithms on the edge. Within this paper, we first propose a formalism to describe relevant datasets and the computing topology. We then evaluate the edge computing approach through a case study involving an edge-based conformance checking algorithm. The results demonstrate the feasibility and benefits of edge-based real-time process mining for enhanced autonomous control in smart factories.

cs.DC

Technology Research Software: An Often Overlooked Category of Research Software

Research software has been categorized for various goals. One fundamental dimension of such categorizations is the role that the software plays in the research process. Recently, a new role category has emerged: technology research software, which covers research software developed in technology research. Until now, this category of technology research software has often been overlooked and neglected within the research software engineering community. In this article, we explain technology research software and its primary subroles. Technology readiness levels are an established method of estimating the maturity of technologies, including software systems. For technology research software, these readiness levels define secondary subroles. To illustrate the concept of technology research software and to make it more tangible, we present examples of research software that, depending on its specific use within or outside of research, take on the role of technology research software as well as that of another research software category.

cs.SE

Know Your Streams: On the Conceptualization, Characterization, and Generation of Intentional Event Streams

The shift toward IoT-enabled, sensor-driven systems has transformed how operational data is generated, favoring continuous, real-time event streams (ES) over static event logs. This evolution presents new challenges for Streaming Process Mining (SPM), which must cope with out-of-order events, concurrent activities, incomplete cases, and concept drifts. Yet, the evaluation of SPM algorithms remains rooted in outdated practices, relying on static logs or artificially streamified data that fail to reflect the complexities of real-world streams. To address this gap, we first perform a comprehensive review of data stream literature to identify stream characteristics currently not reflected in the SPM community. Next, we use this information to extend the conceptual foundation for ES. Finally, we propose Stream of Intent, a prototype generator to produce ES with specific features. Our evaluation shows excellence in producing reproducible, intentional ES for targeted benchmarking and adaptive algorithm development in SPM.

cs.DB

ContinuumConductor : Decentralized Process Mining on the Edge-Cloud Continuum

Process mining traditionally assumes centralized event data collection and analysis. However, modern Industrial Internet of Things systems increasingly operate over distributed, resource-constrained edge-cloud infrastructures. This paper proposes a structured approach for decentralizing process mining by enabling event data to be mined directly within the IoT systems edge-cloud continuum. We introduce ContinuumConductor a layered decision framework that guides when to perform process mining tasks such as preprocessing, correlation, and discovery centrally or decentrally. Thus, enabling privacy, responsive and resource-efficient process mining. For each step in the process mining pipeline, we analyze the trade-offs of decentralization versus centralization across these layers and propose decision criteria. We demonstrate ContinuumConductor at a real-world use-case of process optimazition in inland ports. Our contributions lay the foundation for computing-aware process mining in cyber-physical and IIoT systems.

cs.DC

Determining Window Sizes using Species Estimation for Accurate Process Mining over Streams

Streaming process mining deals with the real-time analysis of event streams. A common approach for it is to adopt windowing mechanisms that select event data from a stream for subsequent analysis. However, the size of these windows denotes a crucial parameter, as it influences the representativeness of the window content and, by extension, of the analysis results. Given that process dynamics are subject to changes and potential concept drift, a static, fixed window size leads to inaccurate representations that introduce bias in the analysis. In this work, we present a novel approach for streaming process mining that addresses these limitations by adjusting window sizes. Specifically, we dynamically determine suitable window sizes based on estimators for the representativeness of samples as developed for species estimation in biodiversity research. Evaluation results on real-world data sets show improvements over existing approaches that adopt static window sizes in terms of accuracy and robustness to concept drifts.

cs.DB

AVOCADO: The Streaming Process Mining Challenge

Streaming process mining deals with the real-time analysis of streaming data. Event streams require algorithms capable of processing data incrementally. To systematically address the complexities of this domain, we propose AVOCADO, a standardized challenge framework that provides clear structural divisions: separating the concept and instantiation layers of challenges in streaming process mining for algorithm evaluation. The AVOCADO evaluates algorithms on streaming-specific metrics like accuracy, Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Processing Latency, and robustness. This initiative seeks to foster innovation and community-driven discussions to advance the field of streaming process mining. We present this framework as a foundation and invite the community to contribute to its evolution by suggesting new challenges, such as integrating metrics for system throughput and memory consumption, and expanding the scope to address real-world stream complexities like out-of-order event arrival.

cs.DB

Interoperability From OpenTelemetry to Kieker: Demonstrated as Export from the Astronomy Shop

The observability framework Kieker provides a range of analysis capabilities, but it is currently only able to instrument a smaller selection of languages and technologies, including Java, C, Fortran, and Python. The OpenTelemetry standard aims for providing reference implementations for most programming languages, including C# and JavaScript, that are currently not supported by Kieker. In this work, we describe how to transform OpenTelemetry tracing data into the Kieker framework. Thereby, it becomes possible to create for example call trees from OpenTelemetry instrumentations. We demonstrate the usability of our approach by visualizing trace data of the Astronomy Shop, which is an OpenTelemetry demo application.

cs.SE

Detection of Performance Changes in MooBench Results Using Nyrki\"o on GitHub Actions

In GitHub with its 518 million hosted projects, performance changes within these projects are highly relevant to the project's users. Although performance measurement is supported by GitHub CI/CD, performance change detection is a challenging topic. In this paper, we demonstrate how we incorporated Nyrki\"o to MooBench. Prior to this work, Moobench continuously ran on GitHub virtual machines, measuring overhead of tracing agents, but without change detection. By adding the upload of the measurements to the Nyrki\"o change detection service, we made it possible to detect performance changes. We identified one major performance regression and examined the performance change in depth. We report that (1) it is reproducible with GitHub actions, and (2) the performance regression is caused by a Linux Kernel version change.

cs.SE

Semantic Zoom and Mini-Maps for Software Cities

Software visualization tools can facilitate program comprehension by providing visual metaphors, or abstractions that reduce the amount of textual data that needs to be processed mentally. One way they do this is by enabling developers to build an internal representation of the visualized software and its architecture. However, as the amount of displayed data in the visualization increases, the visualization itself can become more difficult to comprehend. The ability to display small and large amounts of data in visualizations is called visual scalability. In this paper, we present two approaches to address the challenge of visual scalability in 3D software cities. First, we present an approach to semantic zoom, in which the graphical representation of the software landscape changes based on the virtual camera's distance from visual objects. Second, we augment the visualization with a miniature two-dimensional top-view projection called mini-map. We demonstrate our approach using an open-source implementation in our software visualization tool ExplorViz. ExplorViz is web-based and uses the 3D city metaphor, focusing on live trace visualization. We evaluated our approaches in two separate user studies. The results indicate that semantic zoom and the mini-map are both useful additions. User feedback indicates that semantic zoom and mini-maps are especially useful for large software landscapes and collaborative software exploration. The studies indicate a good usability of our implemented approaches. However, some shortcomings in our implementations have also been discovered, to be addressed in future work. Video URL: https://youtu.be/LYtUeWvizjU

cs.SE

HTML Structure Exploration in 3D Software Cities

Software visualization, which uses data from dynamic program analysis, can help to explore and understand the behavior of software systems. It is common that large software systems offer a web interface for user interaction. Usually, available web interfaces are not regarded in software visualization tools. This paper introduces additions to the web-based live tracing software visualization tool ExplorViz: We add an embedded web view for instrumented applications in the 3D visualization to ease interaction with the given applications and enable the exploration of the thereby displayed HTML content. Namely, the Document Object Model (DOM) is visualized via a three-dimensional representation of the HTML structure in same-origin contexts. Our visualization approach is evaluated in a preliminary user study. The study results give insights into the potential use cases, benefits, and shortcomings of our implemented approach. Based on our study results, we propose directions for further research to support the visual exploration of web interfaces and explore use cases for the combined visualization of software cities and HTML structure. Video URL: https://youtu.be/wBWKlbvzOOE

cs.SE

Dynamic and Static Analysis of Python Software with Kieker Including Reconstructed Architectures

The Kieker observability framework is a tool that provides users with the means to design a custom observability pipeline for their application. Originally tailored for Java, supporting Python with Kieker is worthwhile. Python's popularity has exploded over the years, thus making structural insights of Python applications highly valuable. Our Python analysis pipeline combines static and dynamic analysis in order to build a complete picture of a given system.

cs.SE

Ecoscape: Fault Tolerance Benchmark for Adaptive Remediation Strategies in Real-Time Edge ML

Edge computing offers significant advantages for realtime data processing tasks, such as object recognition, by reducing network latency and bandwidth usage. However, edge environments are susceptible to various types of fault. A remediator is an automated software component designed to adjust the configuration parameters of a software service dynamically. Its primary function is to maintain the services operational state within predefined Service Level Objectives by applying corrective actions in response to deviations from these objectives. Remediators can be implemented based on the Kubernetes container orchestration tool by implementing remediation strategies such as rescheduling or adjusting application parameters. However, currently, there is no method to compare these remediation strategies fairly. This paper introduces Ecoscape, a comprehensive benchmark designed to evaluate the performance of remediation strategies in fault-prone environments. Using Chaos Engineering techniques, Ecoscape simulates realistic fault scenarios and provides a quantifiable score to assess the efficacy of different remediation approaches. In addition, it is configurable to support domain-specific Service Level Objectives. We demonstrate the capabilities of Ecoscape in edge machine learning inference, offering a clear framework to optimize fault tolerance in these systems without needing a physical edge testbed.

cs.PF

Process Mining on Distributed Data Sources

Major domains such as logistics, healthcare, and smart cities increasingly rely on sensor technologies and distributed infrastructures to monitor complex processes in real time. These developments are transforming the data landscape from discrete, structured records stored in centralized systems to continuous, fine-grained, and heterogeneous event streams collected across distributed environments. As a result, traditional process mining techniques, which assume centralized event logs from enterprise systems, are no longer sufficient. In this paper, we discuss the conceptual and methodological foundations for this emerging field. We identify three key shifts: from offline to online analysis, from centralized to distributed computing, and from event logs to sensor data. These shifts challenge traditional assumptions about process data and call for new approaches that integrate infrastructure, data, and user perspectives. To this end, we define a research agenda that addresses six interconnected fields, each spanning multiple system dimensions. We advocate a principled methodology grounded in algorithm engineering, combining formal modeling with empirical evaluation. This approach enables the development of scalable, privacy-aware, and user-centric process mining techniques suitable for distributed environments. Our synthesis provides a roadmap for advancing process mining beyond its classical setting, toward a more responsive and decentralized paradigm of process intelligence.

cs.ET

The Kieker Observability Framework Version 2

Observability of a software system aims at allowing its engineers and operators to keep the system robust and highly available. With this paper, we present the Kieker Observability Framework Version 2, the successor of the Kieker Monitoring Framework. In this tool artifact paper, we do not just present the Kieker framework, but also a demonstration of its application to the TeaStore benchmark, integrated with the visual analytics tool ExplorViz. This demo is provided both as an online service and as an artifact to deploy it yourself.

cs.SE

DPM-Bench: Benchmark for Distributed Process Mining Algorithms on Cyber-Physical Systems

Process Mining is established in research and industry systems to analyze and optimize processes based on event data from information systems. Within this work, we accomodate process mining techniques to Cyber-Physical Systems. To capture the distributed and heterogeneous characteristics of data, computational resources, and network communication in CPS, the todays process mining algorithms and techniques must be augmented. Specifically, there is a need for new Distributed Process Mining algorithms that enable computations to be performed directly on edge resources, eliminating the need for moving all data to central cloud systems. This paper introduces the DPM-Bench benchmark for comparing such Distributed Process Mining algorithms. DPM-Bench is used to compare algorithms deployed in different computational topologies. The results enable information system engineers to assess whether the existing infrastructure is sufficient to perform distributed process mining, or to identify required improvements in algorithms and hardware. We present and discuss an experimental evaluation with DPM-Bench.

cs.SE

Toward Bundler-Independent Module Federations: Enabling Typed Micro-Frontend Architectures

Modern web applications demand scalable and modular architectures, driving the adoption of micro-frontends. This paper introduces Bundler-Independent Module Federation (BIMF) as a New Idea, enabling runtime module loading without relying on traditional bundlers, thereby enhancing flexibility and team collaboration. This paper presents the initial implementation of BIMF, emphasizing benefits such as shared dependency management and modular performance optimization. We address key challenges, including debugging, observability, and performance bottlenecks, and propose solutions such as distributed tracing, server-side rendering, and intelligent prefetching. Future work will focus on evaluating observability tools, improving developer experience, and implementing performance optimizations to fully realize BIMF's potential in micro-frontend architectures.

cs.SE

Fast and Efficient What-If Analyses of Invocation Overhead and Transactional Boundaries to Support the Migration to Microservices

Improving agility and maintainability are common drivers for companies to adopt a microservice architecture for their existing software systems. However, the existing software often relies heavily on the fact that it is executed within a single process space. Therefore, decomposing existing software into out-of-process components like microservices can have a severe impact on non-functional properties, such as overall performance due to invocation overhead or data consistency. To minimize this impact, it is important to consider non-functional properties already as part of the design process of the service boundaries. A useful method for such considerations are what-if analyses, which allow to explore different scenarios and to develop the service boundaries in an iterative and incremental way. Experience from an industrial case study suggests that for these analyses, ease of use and speed tend to be more important than precision. In this paper, we present emerging results for an approach for what-if analyses based on trace rewriting that is (i) specifically designed for analyzing the impact on non-functional properties due to decomposition into out-of-process components and (ii) deliberately prefers ease of use and analysis speed over precision of the results.

cs.SE