Development of a deployment platform for ONNX models

Artificial Intelligence models and specifically Machine Learning models are experiencing increasing adoption in various fields and domains. Consequentially the demand for efficient deployment solutions is becoming urgent. Ensuring seamless model management, reliable deployment and fast inference remains a key challenge. This work presents a solution to the mentioned problem. The solution is a platform for ONNX model deployment, providing a streamlined approach to model versioning, metadata management, and inference execution. To enable the efficient model file storage and their associated metadata, the platform leverages MongoDB alongside GridFS. Additionally the platform manages model versioning, where each model version is stored as a seperate entry, enabling multiple versions of a model to exist without having to delete previous versions. Deployment and inference are tested using performance metrics, like resource utilization and speed. Usability and robustness though are evaluated through structured test cases and user feedback. All in all the goal is to develop a prototype of the platform quickly utilizing rapid prototyping, while iteratively evaluating it with the help of design science. Deployment results indicate efficient resource utilization and rapid inference, with challenges in scalability, especially for large models. Usability testing confirms an intuitive interface, ease of use and general user satisfaction. Robustness testing shows that the platform handles unexpected scenarios effectively without failures, while remaining operable and avoiding complete crashes. Finally the platform successfully addresses ONNX model deployment challenges, while maintaining ease of use, even for non-technical users. Future enhancements could include enhanced model versioning, inference optimizations and integration with external platforms

Improving PPP positioning and troposphere estimates using an azimuth-dependent weighting scheme

Asymmetric troposphere modeling is crucial in Precise Point Positioning (PPP). The functional model of the asymmetric troposphere has been thoroughly studied, while the stochastic model lacks discussion. Currently, there is no suitable stochastic model for asymmetric tropospheric conditions, potentially degrading the positioning accuracy and the reliability of Zenith Total/Wet Delay (ZTD/ZWD) estimates. This paper introduces an Azimuth-Dependent Weighting (ADW) scheme that utilizes information from asymmetric mapping functions to adaptively weight Global Navigation Satellite System (GNSS) observations affected by azimuth-dependent errors. The concept of ADW has been validated using Numerical Weather Prediction data and International GNSS Service data. The results indicate that ADW effectively improves the coordinate repeatability of the PPP solution by approximately 10%in the horizontal and 20%in the vertical direction. Additionally, ADW appears to be capable to improve the ZWD estimates during the PPP convergence period and yields smoother ZWD estimates. Consequently, it is recommended to adopt this new weighting scheme in PPP applications when an asymmetric mapping functions is employed.Projekt DEALChina Scholarship Counci

Vestigial singlet pairing in a fluctuating magnetic triplet superconductor and its implications for graphene superlattices

Stacking and twisting graphene layers allows to create and control a two-dimensional electron liquid with strong correlations. Experiments indicate that these systems exhibit strong tendencies towards both magnetism and triplet superconductivity. Motivated by this phenomenology, we study a 2D model of fluctuating triplet pairing and spin magnetism. Individually, their respective order parameters, d and N , cannot order at finite temperature. Nonetheless, the model exhibits a variety of vestigial phases, including charge-4 e superconductivity and broken time-reversal symmetry. Our main focus is on a phase characterized by finite d  ⋅  N , which has the same symmetries as the BCS state, a Meissner effect, and metastable supercurrents, yet rather different spectral properties: most notably, the suppression of the electronic density of states at the Fermi level can resemble that of either a fully gapped or nodal superconductor, depending on parameters. This provides a possible explanation for recent tunneling experiments in the superconducting phase of graphene moiré systems.Projekt DEA

Propädeutik der Technikwissenschaften : Doktorandenseminar: Wissenschaftstheorie der Technikwissenschaften

Technikwissenschaften im Wissenschaftssystem Vom Forschungsprozess zur Gliederung: Forschungsreise Technikwissenschaftliche Erkenntnis: Begriff & Hypothese Modelltheorie und Systemtheorie Forschungsfrage und Themenfindung Evaluation der Zielerreichung: Verifikation & Validierung Wissenschaftstheoretische Positionierun

Diverse reactivity of a cationic N-heterocyclic phosphenium complex towards anionic substrates : substitution vs. reduction

A cationic N-heterocyclic phosphenium (NHP) iron tetracarbonyl complex was synthesised from the free cation and its behaviour towards various anionic reactants studied. Reactions with fluoride, chloride, and hydride sources proceeded under attachment of the anion at phosphorus to yield Fe(CO)4-complexes of neutral diazaphospholenes, while bromide and iodide reacted under addition of the anion at the metal and decarbonylation to yield NHP iron halides. Reactions with amides and organometallics were unselective. At room temperature, predominantly reduction of the cationic complex to yield a spectroscopically detectable Fe-centred radical and its deactivation products was observable. At -78 °C, CH-metalation at the heterocycle was preferred, as evidenced by the structural characterisation of a neutral borane-adduct of the metalation product of a modified NHP complex. The dimer of the Fe-centred radical formed also in reactions of chloro- and bromo-diazaphospholenes with Fe2(CO)9, which proceed not only by complexation of the P-donors as expected, but involve also oxidative addition steps and single electron transfer processes in which excess iron complex acts as the reductant. The title complex and the products isolated in the reaction studies were characterised by spectroscopic data and in many cases by XRD studies. Computational studies were employed to analyse the differing reactivity of the cationic NHP complex towards light and heavy halide ions, and to help in the assignment of the radical intermediate observed. The more diverse reactivity of the cationic NHP complexes compared to their neutral analogues is attributed to their higher electrophilicity.Deutsche ForschungsgemeinschaftMinisterium für Wissenschaft, Forschung und Kunst Baden-Württember

Material availability in fluid assembly systems

Ausgangspunkt der vorliegenden Arbeit ist die aus den Defiziten starr verketteter Fließmontagelinien resultierende Forderung nach veränderungsfähigen Systemen für die zukünftige Automobilmontage. Als Ausprägungsform eines veränderungsfähigen Systems grenzt die fluide Montage, die im Kontext des Forschungscampus ARENA2036 erarbeitet wird und über eine spezifische Anzahl an Freiheitsgraden verfügt, den Untersuchungsbereich dieser Arbeit ab. Es zeigt sich, dass in dieser Umgebung die Gewährleistung der kurzfristigen Materialverfügbarkeit infolge dynamischer Materialflussstrukturen eine besondere Herausforderung darstellt. Aus diesem Grund beschäftigt sich die vorliegende Arbeit mit der übergeordneten Forschungsfrage, wie sich die Materialverfügbarkeit während des Betriebs eines fluiden Montagesystems sicherstellen lässt. Als konkreter Handlungsbedarf wird die Entwicklung und Untersuchung einer Methodik zur Überprüfung und Sicherstellung der Materialverfügbarkeit in fluiden Montagesystemen identifiziert. Die entwickelte Methodik setzt sich aus vier aufeinanderfolgenden Prozessschritten zusammen. Hierbei handelt es sich um die Schritte Initialisierung, Zielsuche und Aufgabenableitung, Lösungssuche sowie Lösungsauswahl. Die Methodik ist als Bestandteil des Materialbereitstellungssystems dem Aufgabenfeld der Logistik zugeordnet und trägt zur Koordination des Montage- und Materialbereitstellungssystems bei, da sie an der Schnittstelle dieser beiden Systeme eingesetzt wird. Die simulationsbasierte Untersuchung der Methodik erfolgt am Beispiel einer Cockpit-Vormontage. Verschiedene Experimente werden durchgeführt, um die Funktionsweise der Methodik zu erproben und den Einfluss verschiedener Größen auf die Materialverfügbarkeit zu analysieren. Wie die Simulationsergebnisse zeigen, gelingt es durch den Einsatz der Methodik, die Materialverfügbarkeit in fluiden Montagesystemen während des laufenden Betriebs sicherzustellen. Hierbei hat sich insbesondere die Verwendung des Ansatzes zur logistik- und montageinduzierten Materialverfügbarkeit als förderlich erwiesen. Dadurch leistet die vorliegende Arbeit einen Beitrag zur Ausgestaltung der Materialbereitstellung in fluiden Montagesystemen

The size of the functional base of support decreases with age

Falls occur more often as we age. To identify people at risk of falling, balance analysis requires an accurate base-of-support model. We previously developed a functional base-of-support (fBOS) model for standing young adults and showed that its area is smaller than the footprint area. Our fBOS model is a polygon that contains centre-of-pressure trajectories recorded as standing participants move their bodies in the largest possible loop while keeping their feet flat on the ground. Here we assess how the size of the fBOS area changes with age by comparing 38 younger (YA), 14 middle-aged (MA), and 34 older adults (OA). The fBOS area is smaller in older adults: OA area is 58% of the YA area (p<0.001), and 59% of the MA area (p=0.001), with no difference between YA and MA. The reduction in fBOS area among the OA is primarily caused by a reduction in the length of the fBOS. In addition, among older adults smaller fBOS areas correlated with a lower score on the Short Physical Performance Battery (τ=0.28, p=0.04), a reduced walking speed (τ=0.25, p=0.04), and a higher frailty level (p=0.09). So that others can extend our work, we have made our fBOS models available online

Mitigating the amorphization of perovskite layers by using atomic layer deposition of alumina

Atomic layer deposition of aluminum oxide (ALD-Al2O3) layers has recently been studied for stabilizing perovskite solar cells (PSCs) against environmental stressors, such as humidity and oxygen. In addition, the ALD-Al2O3 layer acts as a protective barrier, mitigating pernicious halide ion migration from the perovskite towards the hole transport interface. However, its effectiveness in preventing the infiltration of ions and additives from the hole-transport layer into perovskites remains insufficiently understood. Herein, we demonstrate the deposition of a compact ultrathin (∼0.75 nm) ALD-Al2O3 layer that conformally coats the morphology of a triple-cation perovskite layer. This promotes an effective contact of the hole transporter layer on top of the perovskite, thereby improving the charge carrier collection between these two layers. Upon systematically investigating the layer-by-layer structure of the PSC, we discovered that ALD-Al2O3 also acts as a diffusion barrier for the degraded species from the adjacent transport layer into the perovskite. In addition to these protective considerations, ALD-Al2O3 impedes the transition of crystalline perovskites to an undesired amorphous phase. Consequently, the dual functionality (i.e., enhanced contact and diffusion barrier) of the ALD-Al2O3 protection enhanced the device performance from 19.1% to 20.5%, while retaining 98% of its initial performance compared to <10% for pristine devices after 1500 h of outdoor testing under ambient conditions. Finally, this study deepens our understanding of the mechanism of ALD-Al2O3 as a two-way diffusion barrier, highlighting the multifaceted role of buffer layers in interfacial engineering for the long-term stability of PSCs.Deutsche ForschungsgemeinschaftBundesministerium für Bildung und ForschungEuropean UnionMinisterstvo Školství, Mládeže a TělovýchovyBundesministerium für Wirtschaft und Klimaschut

Functors for ordinary and stable simplicial groups : a connection to Conduché's stable crossed modules

I. A simplicial group models a pointed connected topological space up to homotopy. We may truncate a simplicial group in such a way that the homotopy groups in positions n and 0 are preserved. In this way, we obtain an [n,0]-simplicial group. This process gives a truncation functor from the category of simplicial groups to the category of [n,0]-simplicial groups. We construct the right-adjoint to this truncation functor that preserves homotopy groups, using methods from Conduché. II. A stable simplicial group, also called group spectrum or Kan spectrum, models a topological spectrum up to homotopy. We construct adjoint functors between the category of stable simplicial groups and the category of [n,-∞]-stable simplicial groups that respect homotopy groups. The category of [1,0]-stable simplicial groups is defined as a full subcategory of [1,-∞]-stable simplicial groups. We show that the category of [1,0]-stable simplicial groups is equivalent to the category of stable crossed modules in the sense of Conduché, using a construction of countably iterated semidirect products

Flat combining for non-volatile main memory

The availability of non-volatile random-access memory (NVRAM) spurred interest in its potential as a foundation for high-performance, persistent data structures. Our work focuses on applying and evaluating the flat combining synchronization paradigm on persistent memory systems. We present a novel approach, named persistent flat combining (PFC), along with a simplified version called fast persistent flat combining (FPFC), which is more efficient but has more limited use cases. Our algorithms combine operations from multiple threads into batches, leveraging not only the well-known benefits of general software combining but also the unique characteristics of NVRAM to develop a high-performance, persistent resizable array together with a persistent memory allocator. Our experimental evaluation, conducted on Intel’s Optane persistent memory platform, demonstrates the effectiveness of our implementation and shows substantial performance improvements over traditional locking mechanisms and other state-of-the-art persistent software combining techniques. We show that at high concurrency levels, our approach outperforms detectable flat combining (DFC) by a factor greater than 10 and PBstack (a persistent stack based on PBcomb) by a factor greater than 2.Die Verfügbarkeit non-volatile random-access memory (NVRAM) weckte das Interesse an seinem Potenzial als Grundlage für hochperformante, persistente Datenstrukturen. Unsere Arbeit konzentriert sich auf die Anwendung und Evaluierung des flat-combining Synchronisationsparadigmas auf persistenten Speichersystemen. Wir präsentieren einen neuen Ansatz, gennant persistent flat combining (PFC), sowie eine vereinfachte Version namens fast persistent flat combining (FPFC), die effizienter ist, aber enger begrenzte Anwendungsmöglichkeiten hat. Unsere Algorithmen kombinieren Operationen von mehreren Threads zu Stapeln und nutzen dabei nicht nur die bekannten Vorteile des allgemeinen Software-Combinings, sondern auch die einzigartigen Eigenschaften von NVRAM, um ein hochleistungsfähiges, persistentes, größenveränderliches Array zusammen mit einem persistenten Allocator zu entwickeln. Unsere experimentelle Auswertung, die auf Intels Optane persistent memory platform durchgeführt wurde, demonstriert die Effektivität unserer Implementierung und zeigt erhebliche Leistungsverbesserungen gegenüber traditionellen Locking-Mechanismen und anderen aktuellen persistenten Software-Combining-Techniken. Wir zeigen, dass unser Ansatz bei hoher Parallelität detectable flat combining (DFC) um einen Faktor von mehr als 10 und PBstack (ein auf PBcomb basierender persistenter Stack) um einen Faktor von mehr als als 2, übertrifft