Browsing by Author "Bauer, Florian"

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Open Access
Consistent pruning and simplification of administrative subdivisions in OpenStreetMap
(2022) Bauer, Florian
Appealing and efficient map representations rely on simplifying their map elements in order to reduce the amount of data and rendered objects. However, simplifications inside the well-known OpenStreetMap database are not trivial due to nesting and the associated complex dependencies among elements. A good and consistent simplification of elements in a big way is, therefore, not feasible when working on this data. This thesis aims to develop a consistent simplification strategy for administrative boundaries inside the OpenStreetMap database. In order to achieve this goal, the relevant map data inside the database gets filtered and transformed into an independent graph representation. Based on this representation, we develop different approaches to simplify, store and unpack the administrative boundaries based on their administrative levels and structure. Therefore, we introduce multiple consistent simplification approaches based on approximation and pruning, a geographical data structure for efficiently storing and accessing geographical data, and different approaches for unpacking simplified data. Furthermore, we implement a progressive web application that uses the previously defined algorithms and an evaluation proxy for analysing the interaction between components. Finally, all components are benchmarked with static and dynamic analysis regarding the different approaches.
Open Access
Real-time and post-hoc-visualizations of keyboard performances as a support for music education
(2020) Bauer, Florian
Wir haben einen Prototyp für die Visualisierung von Fehlern beim Üben am Klavier entwickelt. Dieser Prototyp soll Klavieranfängern, die noch kein gut entwickeltes Gehör haben, den Einstieg erleichtern und ihnen helfen, ihre eigenen Fehler besser zu erkennen. In unseren Visualisierungen können Noten in klassischer Notation, in Blocknotation oder als Piano Roll dargestellt werden. Noten in der Blocknotation haben die Form eines Rechtecks mit abgerundeten Ecken und werden anstelle der klassischen Notenköpfe mit einer ihrer Dauer entsprechenden Länge gezeichnet. Der Benutzer kann sein Klavierspiel live visualisieren, speichern und die Aufnahmen später analysieren. Aufnahme- und ground truth Noten werden je nach Notation und Visualisierung nebeneinander oder aufeinander visualisiert. Wir haben einen Algorithmus entwickelt, der aufgezeichnete und ground truth Noten miteinander vergleicht, damit die enthaltene Fehler farbkodierte werden können. Basierend auf der Piano Roll entwarfen wir eine Heatmap-Visualisierung, bei der alle Noten in Zeitscheiben unterteilt werden und diese Scheiben unterschiedliche Farben erhalten, je nachdem, ob die Aufnahme- und die ground truth Note in derselben Zeitscheibe liegen. In unserer Auswertung durch eine Fallstudie kamen wir zu dem Schluss, dass nur die Piano Roll Notation geeignet ist, mehrere Aufnahmen gleichzeitig zu visualisieren. Die Blocknotation eignet sich für die Darstellung des Vergleichs einzelner Aufnahmen. Außerdem ist die klassische Notation in diesem Stadium im Allgemeinen ungeeignet, da in ihr mehrere Noten in einem engen Bereich schnell unübersichtlich werden. Der Fehleranalyse-Algorithmus erfüllt seinen Zweck, wenn das vorgegebene Tempo eingehalten wird. Andernfalls kann es vorkommen, dass Noten falsch zugeordnet werden.
Open Access
Scheduling with uncertainty for Time-Sensitive Networking using robust optimization techniques and integer linear programming
(2024) Bauer, Florian
Application services depend on the network to guarantee reliability, which is critical for safety and correct operation. Time-Sensitive Networking is a technology for reliable real-time communication of time-sensitive applications. While many schedulers exist that provide reliability for wired Time-Sensitive Networks (TSN) with the assumption of deterministic packet delays, scheduling for wireless TSN with uncertain packet delays has received significantly less attention. This work leverages the methodology of Robust Optimization (RO) to propose a robust scheduling approach that ensures provable reliability for both wired and wireless TSN. An uncertainty set defines the range of possible values, ensuring that the schedule remains feasible under all possible realizations within this set. As uncertainty sets are a key component in RO, we introduce methods to compute boxed and polytope uncertainty sets containing possible packet delays based on a set of given reliability requirements. A scheduler is deemed robust if it satisfies the given reliability constraints for all possible packet delays within the computed uncertainty set. Although robustness can be achieved through strict isolation and conservative filtering of packets, we demonstrate that several limitations prevent known robust schedulers from fully exploiting arbitrary uncertainty set shapes. As certain problem instances are unsolvable using simple boxed uncertainty sets, we indicate the need for schedulers that can utilize complex shapes of uncertainty sets rather than boxes. In response to this challenge, we introduce Uncertain No-Wait Packet Scheduling (UNWPS), a scheduler capable of computing robust schedules, and prove that UNWPS is robust against arbitrary upper-bounded boxed and polytope uncertainty sets. We assess the influence of uncertainty sets on the quality of the resulting UNWPS schedules, compare their performances to the performance of other robust scheduling approaches across various exemplary TSN networks and message stream configurations and carry out simulations conducted using the DetCom simulation framework to validate the robustness of UNWPS empirically.