13 Zentrale Universitätseinrichtungen

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/14

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Open Access
42: Das Erste-Hilfe-System im WWW
(1997) Löffler, Sandra; Höschele, Britta; Lasermann, Markus
42 ist ein Erste-Hilfe-System, das vor allem anfängliche Fragen zur Benutzung der Soft- und Hardware des Rechenzentrums der Universität Stuttgart klären soll. Das Erste-Hilfe-System wurde in erster Linie entwickelt, um Benutzerinnen und Benutzern den Start in die Arbeit mit den Rechnern am RUS zu erleichtern. Es soll vor allem grundlegende Kenntnisse über die Rechnernutzung vermitteln und einen Überblick über die wichtigsten Themenbereiche geben. Benutzerinnen und Benutzer, die bereits einige Erfahrung mit Rechnern haben, können das Erste-Hilfe-System als Gedächtnisstütze nutzen.
Open Access
Accelerated 2D visualization using adaptive resolution scaling and temporal reconstruction
(2023) Becher, Michael; Heinemann, Moritz; Marmann, Thomas; Reina, Guido; Weiskopf, Daniel; Ertl, Thomas
Data visualization relies on efficient rendering to allow users to interactively explore and understand their data. However, achieving interactive frame rates is often challenging, especially for high-resolution displays or large datasets. In computer graphics, several methods temporally reconstruct full-resolution images from multiple consecutive lower-resolution frames. Besides providing temporal image stability, they amortize the rendering costs over multiple frames and thus improve the minimum frame rate. We present a method that adopts this idea to accelerate 2D information visualization, without requiring any changes to the rendering itself. By exploiting properties of orthographic projection, our method significantly improves rendering performance while minimizing the loss of image quality during camera manipulation. For static scenes, it quickly converges to the full-resolution image. We discuss the characteristics and different modes of our method concerning rendering performance and image quality and the corresponding trade-offs. To improve ease of use, we provide automatic resolution scaling in our method to adapt to user-defined target frame rate. Finally, we present extensive rendering benchmarks to examine real-world performance for examples of parallel coordinates and scatterplot matrix visualizations, and discuss appropriate application scenarios and contraindications for usage.
Open Access
AIX 4.1- Installations-Service
(1996) Frasch, Hermann
Der in der BI. 10/11 95 (Neues zum AIX-Installations-Service, S. 37 ff.) angekündigte Installations-Service für AIX Version 4.1 auf IBM RS/6000-Rechnern hat - schneller alsgedacht - die Testphase überschritten und ist bereits in voller Produktion. Im folgenden soll die Konzeption des Network Installation Management-Systems, der Umfang des aktuellen Service-Angebots und die Vorgehensweise bei der Netz-Installation von RS/6000-Rechnern näher beschrieben werden.
Open Access
Analysis of hydrogen-induced changes in the cyclic deformation behavior of AISI 300-series austenitic stainless steels using cyclic indentation testing
(2021) Brück, Sven; Blinn, Bastian; Diehl, Katharina; Wissing, Yannick; Müller, Julian; Schwarz, Martina; Christ, Hans-Jürgen; Beck, Tilmann; Staedler, Thorsten; Jiang, Xin; Butz, Benjamin; Weihe, Stefan
The locally occurring mechanisms of hydrogen embrittlement significantly influence the fatigue behavior of a material, which was shown in previous research on two different AISI 300-series austenitic stainless steels with different austenite stabilities. In this preliminary work, an enhanced fatigue crack growth as well as changes in crack initiation sites and morphology caused by hydrogen were observed. To further analyze the results obtained in this previous research, in the present work the local cyclic deformation behavior of the material volume was analyzed by using cyclic indentation testing. Moreover, these results were correlated to the local dislocation structures obtained with transmission electron microscopy (TEM) in the vicinity of fatigue cracks. The cyclic indentation tests show a decreased cyclic hardening potential as well as an increased dislocation mobility for the conditions precharged with hydrogen, which correlates to the TEM analysis, revealing courser dislocation cells in the vicinity of the fatigue crack tip. Consequently, the presented results indicate that the hydrogen enhanced localized plasticity (HELP) mechanism leads to accelerated crack growth and change in crack morphology for the materials investigated. In summary, the cyclic indentation tests show a high potential for an analysis of the effects of hydrogen on the local cyclic deformation behavior.
Open Access
Analytical description of the criterion for the columnar-to-equiaxed transition during laser beam welding of aluminum alloys
(2021) Böhm, Constantin; Hagenlocher, Christian; Wagner, Jonas; Graf, Thomas; Weihe, Stefan
Open Access
Anisotropy of the tribological performance of periodically oxidated laser-induced periodic surface structures
(2023) Onufrijevs, Pavels; Grase, Liga; Padgurskas, Juozas; Rukanskis, Mindaugas; Durena, Ramona; Willer, Dieter; Iesalnieks, Mairis; Lungevics, Janis; Kaupuzs, Jevgenijs; Rukuiža, Raimundas; Kriūkienė, Rita; Hanesch, Yuliya; Speicher, Magdalena
Laser-induced periodic surface structures (LIPSS) enable advanced surface functionalization with broad applications in various fields such as micro- and nanoelectronics, medicine, microbiology, tribology, anti-icing systems, and more. This study demonstrates the possibility of achieving anisotropy in the tribological behavior of C45-grade steel structured by nanosecond laser radiation using the LIPSS method. The lateral surface of the steel roller was irradiated with a pulsed Nd:YAG laser at an optimum intensity I = 870 MW/cm2 for the formation of LIPSS. Two sets of samples were formed with LIPSS that were perpendicular and parallel to the roller’s rotational motion direction. The Raman intensity maps revealed that the LIPSS structure consisted of periodically arranged oxides at the top of hills. At the same time, the valleys of the LIPSS structures were almost not oxidized. These results correlated well with scanning electron microscopy energy dispersive X-ray spectroscopy mapping and atomic force microscopy measurements. A comparison of Raman and X-ray photoelectron spectroscopy spectra revealed that both the magnetite phase and traces of the hematite phase were present on the surface of the samples. Tribological tests were performed in two cycles with periodic changes in the normal clamping force and sliding speed. It was found that the LIPSS structures which were formed perpendicularly to the sliding direction on the roller had a significantly greater impact on the friction processes. Structures oriented perpendicular to the direction of motion had a positive influence on reducing the energy consumption of a friction process as well as increasing the wear resistance compared to LIPSS formed parallel to the direction of motion or ones having a non-texturized surface. Laser texturing to produce LIPSS perpendicular to the direction of motion could be recommended for friction pairs operating under low-load conditions.
Open Access
'Der Asra' - ein bosnisches Volkslied und/oder eine Übersetzung aus Heine? : zu einem ungeklärten Thema
(2001) Pertschi, Ottmar
In Bosnien und Serbien wird Heines Gedicht 'Der Asra' als ein Volkslied gesungen. Mehrfache Vertonungen liegen vor. Unklar ist, wie es zu diesem serbokroatischen Text kam, da die nachgewiesenen elf Übersetzungen dieses Gedichts nicht mit dem Volksliedtext übereinstimmen. Es werden die Möglichkeiten der Entstehung dieser bislang nicht zuweisbaren Übersetzung aufgezeigt.
Open Access
Beschreibung einer Vorrichtung zur Beförderung einer Flüssigkeit aus Unterdruckgefäßen in ein Medium mit Überdruck
(2008) Suchov, Vladimir G.; Elin, I. I.; Berezovskij, N. E.; Akkerman, I. N.; Pertschi, Ottmar (Übersetzer)
Patentbeschreibung einer Vorrichtung, mit der Flüssigkeiten aus Unterdruckgefäßen in ein Medium mit Überdruck befördert werden können und die darauf beruht, daß die in Reihe angeordneten Aufnahmegefäße einerseits im Vakuum, andererseits mit Normaldruck arbeiten
Open Access
Beschreibung eines Rauchgas-Luftvorwärmers
(1988) Suchov, Vladimir G.; Pertschi, Ottmar (Übersetzer)
Erfinder-Patent Nr 2520 vom 31. März 1927 über einen Rauchgas-Luftvorwärmer aus Wellblech
Open Access
Beschreibung eines Wasserrohr-Dampfkessels
(1988) Suchov, Vladimir G.; Pertschi, Ottmar (Übersetzer)
Erfinder-Patent Nr 1596 vom 16. Februar 1925 über einen Wasserrohr-Dampfkessel mit senkrecht eingebrachter Batterie von Rohren, die mit Hilfe von Rohranschlußstücken in einzelnen Elementen zusammengeführt werden
Open Access
Brennpunkt Wavelets
(1997) Fischer, Thomas; Haase, Maria
Im multimedialen Zeitalter müssen immer größere Datenmengen analysiert, gespeichert und übertragen werden. Um Engpässe oder gar Staus auf den Daten Highways zu vermeiden, wird es zunehmend wichtiger, den Datentransfer über das Netz - insbesondere von Bildern - möglichst schnell und kostengünstig durchzuführen. Software-Hersteller und Online-Anbieter versuchen folgerichtig, effiziente, der Anwendung angepaßte, Kompressionstechniken bereitzustellen, die die Information möglichst dichtgepackt übertragen. Im Wettstreit zwischenden verschiedenen Kompressionsverfahren gewinnen Wavelet-Algorithmen immer mehr an Bedeutung.
Open Access
Can a hand-held 3D scanner capture temperature-induced strain of mortar samples : comparison between experimental measurements and numerical simulations
(2023) Haynack, Alexander; Zadran, Sekandar; Timothy, Jithender J.; Gambarelli, Serena; Kränkel, Thomas; Thiel, Charlotte; Ožbolt, Joško; Gehlen, Christoph
The expected lifespan of cement-based materials, particularly concrete, is at least 50 years. Changes in the pore structure of the material need to be considered due to external influences and associated transport processes. The expansion behaviour of concrete and mortar during freeze-thaw attacks, combined with de-icing salt agents, is crucial for both internal and external damage. It is essential to determine and simulate the expansion behaviour of these materials in the laboratory, as well as detect the slow, long-term expansion in real structures. This study measures the expansion of mortar samples during freeze-thaw loading using a high-resolution hand-held 3D laser scanner. The specimens are prepared with fully or partially saturated pore structures through water storage or drying. During freeze-thaw experiments, the specimens are exposed to pure water or a 3% sodium chloride solution (NaCl). Results show contraction during freezing and subsequent expansion during thawing. Both test solutions exhibit similar expansion behaviour, with differences primarily due to saturation levels. Further investigations are required to explore the changing expansion behaviour caused by increasing microcracking resulting from continuous freeze-thaw cycles. A numerical analysis using a 3D coupled hygro-thermo-mechanical (HTM) model is conducted to examine the freeze–thaw behaviour of the mortar. The model accurately represents the freezing deformation during the freeze–thaw cycle.
Open Access
Challenge: die Herausforderung - Die Verschlüsselungsfreiheit - Die Hamburger Erklärung
(1997) Ehnis, Lothar; Springer, Helmut
Die Geheim- oder die Zeichensprache, bei der ein nebenstehender Dritter die Unterhaltung der Kommunizierenden nicht verstehen kann, hat Menschen schon immer fasziniert. Jedoch haben derart Kommunizierende auch schon immer einen gewissen negativen Verdacht auf sich gelenkt. Besonders Regierungen, Behörden und auch Vorgesetzten kann solches Tun ein Dorn im Auge sein.
Open Access
Characterisation of adobe and mud-straw for the restoration and rehabilitation of Persian historical adobe buildings
(2024) Hejazi, Bina; Luz, Corinna; Grüner, Friedrich; Frick, Jürgen; Garrecht, Harald
In the restoration or rehabilitation of traditional buildings, compatible materials with known characteristics must be used. However, the existing literature lacks comprehensive studies on the characterisation of Persian mud-straw plaster, focusing primarily on Persian adobe. Moreover, previous research on Persian adobe has primarily employed XRF and XRD tests, neglecting ion chromatography, moisture sorption isotherm determination, and thermogravimetric analysis with differential scanning calorimetry. Consequently, there is a shortage of information regarding the elemental composition, mineralogical characteristics, moisture sorption behaviour, and thermal properties of Persian mud–straw plaster, as well as Persian adobe bricks. This paper aims to address this research gap by examining historical and new adobe bricks and mud–straw plaster used in Iran, utilising a comprehensive array of analytical techniques. The results from XRF analysis reveal relatively similar chemical compositions across all samples, while XRD analysis indicates predominantly similar mineral phases. Ion chromatography results demonstrate higher conductivity and chloride concentrations in the mud–straw samples than the adobe samples, with higher values for new samples than historical ones. Freshly used straw, clay, or soil may have higher chloride concentrations caused by the arid climate and soil salinisation in the area. Additionally, moisture sorption isotherm determination results show that adobe and mud–straw plaster with a higher salt load of chlorides have significantly higher moisture absorption. The increased straw quantity in the samples increases the moisture content. Furthermore, thermogravimetric analysis and differential scanning calorimetry indicate that, at low heating, adobe and mud–straw plaster lose water due to dehydration, and at high heating, they lose carbon dioxide due to decarboxylation. The comprehensive characterisation of Persian adobe and mud–straw plaster in this study fills a significant gap in the literature and offers invaluable insights for informing restoration and rehabilitation processes, ensuring the compatibility of the materials used.
Open Access
Coherent mesh representation for parallel I/O of unstructured polyhedral meshes
(2024) Weiß, R. Gregor; Lesnik, Sergey; Galeazzo, Flavio C. C.; Ruopp, Andreas; Rusche, Henrik
This paper presents a new mesh data layout for parallel I/O of linear unstructured polyhedral meshes. The new mesh representation infers coherence across entities of different topological dimensions, i.e., grid cells, faces, and points. The coherence due to cell-to-face and face-to-point connectivities of the mesh is formulated as a tree data structure distributed across processors. The mesh distribution across processors creates consecutive and contiguous slices that render an optimized data access pattern for parallel I/O. A file format using the coherent mesh representation, developed and tested with OpenFOAM, enables the usability of the software at unprecedented scales. Further implications of the coherent and sliceable mesh representation arise due to simplifications in partitioning and diminished pre- and post-processing overheads.
Open Access
Compressive fatigue investigation on high-strength and ultra-high-strength concrete within the SPP 2020
(2022) Basaldella, Marco; Jentsch, Marvin; Oneschkow, Nadja; Markert, Martin; Lohaus, Ludger
The influence of the compressive strength of concrete on fatigue resistance has not been investigated thoroughly and contradictory results can be found in the literature. To date, the focus of concrete fatigue research has been on the determination of the numbers of cycles to failure. Concerning the fatigue behaviour of high-strength concrete (HPC) and, especially, ultra-high-strength concrete (UHPC), which is described by damage indicators such as strain and stiffness development, little knowledge is available, as well as with respect to the underlying damage mechanisms. This lack of knowledge has led to uncertainties concerning the treatment of high-strength and ultra-high-strength concretes in the fatigue design rules. This paper aims to decrease the lack of knowledge concerning the fatigue behaviour of concrete compositions characterised by a very high strength. Within the priority programme SPP 2020, one HPC and one UHPC subjected to monotonically increasing and cyclic loading were investigated comparatively in terms of their numbers of cycles to failure, as well as the damage indicators strain and stiffness. The results show that the UHPC reaches a higher stiffness and a higher ultimate strain and strength than the HPC. The fatigue investigations reveal that the UHPC can resist a higher number of cycles to failure than the HPC and the damage indicators show an improved fatigue behaviour of the UHPC compared to the HPC.
Open Access
Container orchestration on HPC systems through Kubernetes
(2021) Zhou, Naweiluo; Georgiou, Yiannis; Pospieszny, Marcin; Zhong, Li; Zhou, Huan; Niethammer, Christoph; Pejak, Branislav; Marko, Oskar; Hoppe, Dennis
Containerisation demonstrates its efficiency in application deployment in Cloud Computing. Containers can encapsulate complex programs with their dependencies in isolated environments making applications more portable, hence are being adopted in High Performance Computing (HPC) clusters. Singularity, initially designed for HPC systems, has become their de facto standard container runtime. Nevertheless, conventional HPC workload managers lack micro-service support and deeply-integrated container management, as opposed to container orchestrators. We introduce a Torque-Operator which serves as a bridge between HPC workload manager (TORQUE) and container orchestrator (Kubernetes). We propose a hybrid architecture that integrates HPC and Cloud clusters seamlessly with little interference to HPC systems where container orchestration is performed on two levels.
Open Access
CSCW über internationale ATM-Netzwerke - Spock
(1998) Rainer, Daniela; Stoy, Robert
SPOCK (Schnelle Produktentwicklung durch Optimierte Computerbasierte Kommunikation) ist eines von 19 Projekten im Rahmen der G7-GIBN Initiative. Das Ziel des Projektes ist die Einführung von CSCW (Computer Supported Collaborative Working) bei den Partnern von Airbus Industries. Im Airbus Industries-Konsortium arbeiten Ingenieure aus verschiedenen europäischen Ländern zusammen an einem Produkt. Dabei besteht ein großer Bedarf an Kommunikation und Datenaustausch, der bisher noch weitgehend ohne CSCW gehandhabt wird. Am Beispiel des aerodynamischen Tragflächen-Entwurfs, der aus den Teildisziplinen Strömungssimulation, Windkanal-Experiment und Flugversuch besteht, soll das Potential von CSCW-Technologien demonstriert werden. Die Deutsche Telekom und andere europäische Telekommunikationsgesellschaften haben mit einem auf ATM-Technologie basierendem Hochgeschwindigkeitsnetz die Grundlage für weltweit verteiltes kooperatives Arbeiten zur Verfügung gestellt.
Open Access
Datamator : an authoring tool for creating datamations via data query decomposition
(2023) Guo, Yi; Cao, Nan; Cai, Ligan; Wu, Yanqiu; Weiskopf, Daniel; Shi, Danqing; Chen, Qing
Datamation is designed to animate an analysis pipeline step by step, serving as an intuitive and efficient method for interpreting data analysis outcomes and facilitating easy sharing with others. However, the creation of a datamation is a difficult task that demands expertise in diverse skills. To simplify this task, we introduce Datamator, a language-oriented authoring tool developed to support datamation generation. In this system, we develop a data query analyzer that enables users to generate an initial datamation effortlessly by inputting a data question in natural language. Then, the datamation is displayed in an interactive editor that affords users the ability to both edit the analysis progression and delve into the specifics of each step undertaken. Notably, the Datamator incorporates a novel calibration network that is able to optimize the outputs of the query decomposition network using a small amount of user feedback. To demonstrate the effectiveness of Datamator, we conduct a series of evaluations including performance validation, a controlled user study, and expert interviews.
Open Access
DCE/DFS: Produktionsaufnahme
(1996) Rentschler, Gerhard
Mit der Umstellung der Benutzernummern am 01. Juli ist die Produktionsaufnahme mitDCE/DFS verbunden. Neue Benutzer, die auf dem SERVus einschließlich der SP2 rechnen wollen, bekommen kein Heimatverzeichnis im AFS sondern im DFS. Bisherige Benutzer, die ihr Heimatverzeichnis im AFS haben, verbleiben einstweilen dort. Auf Antrag können Sie ins DFS transferiert werden. Bis auf weiteres bleibt auf den SERVus-Rechnern einschließlich SP2 auch die AFS-Software installiert. Welche Vorteile bringt das DFS? Im Gegensatz zu AFS kann auf das DFS auch von den Cray-Rechnern zugegriffen werden. Es ist weiterhin geplant, bestimmte Filesysteme der Cray-Rechner im DFS zur Verfügung zu stellen.