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Christoph Dientzenhofer (1655–1722) is considered one of the most important Baroque master builders of Central Europe. From his extensive architectural oeuvre, a group of six church buildings with geometrically complex forms stands out, recognised by architectural historians as particularly innovative and influential. These churches, located in Bohemia (Czech Republic), and often collectively referred to as the ‘radical’, ‘dynamic’, ‘Guarinesque’, or simply ‘Bohemian’ group, are: St. Joseph in Obořiště (1702–11), the Castle Church in Smiřice (1702–11), St. Nicholas in the Lesser Town of Prague (1703–11), St. Clare in Cheb (1707–11), St. Margaret in Břevnov (1708–16), and the Church of the Holy Assumption in Nová Paka (1709–24). The brick vaults of these six buildings, sequences of oval domes and double-curved vault areas, are of particular interest for building research. In this study, the geometric design of the vaults of Dientzenhofer’s ‘radical’ churches is documented, analysed, and compared using 3D laser scans of the buildings as primary source. The 3D models generated from the scans enable a geometric analysis through the method of reverse geometric engineering, breaking down the vaults’ complex three-dimensional forms into their basic two-dimensional components: segments of circles with different radii and orientations, curved in one or two directions. These forms can be found in the architectural and stereotomic treatises that were widespread at the time. By comparing the vault geometry of the six churches with each other and with the geometric concepts discussed in the treatises, general statements can be made about the architect’s design choices. On the basis of this investigation, hypotheses are made about the design and underlying geometric ideas of the vaults of Dientzenhofer’s ‘radical group’, and the results are placed in context.
High Medieval chimneys, although often the focal point of contemporary representative buildings, are rarely a topic of construction history. More often they appear in art or architectural history where they are discussed regarding their style and ornamentation. It is however worthwhile to examine these important representative objects with the tools of the construction historian. In them, we can find important information regarding the contemporary craftsmanship and skills. Based on extensive firsthand examinations and building archaeology this paper aims to discuss the planning and building process of the highly complex cut-stone chimney system in the keep of Schönburg Castle (1201 CE) using new methods of reverse engineering.
Nostocales form thick-walled, resting cells (akinetes) for overwintering in lake sediments of Central Europe. The pelagic Nostocales population recruits after the germination of akinetes, which mainly takes place in the spring with increasing temperatures and light intensities. The study aimed to i) characterize the sediment surfaces inhabited by viable akinetes that potentially contribute to the formation of a pelagic population, and ii) estimate the inoculum size of the available sedimentary akinete pool. We investigated the horizontal distribution of akinetes in sediments and the seasonal course of light and temperature in two deep dimictic lakes (Lake Stechlinsee, max. depth 69 m and Lake Scharmützelsee, max. depth 29.5 m; NE Germany). The akinete pool was calculated and the potential inoculum was estimated using assumed light and temperature data for akinete germination. The akinete abundance in sediments depended on the basin morphometry and increased with water depth. Only a small proportion of the viable akinete pool in shallow water areas contributed as inoculum to pelagic population. The potential inoculum size in Lake Scharmützelsee was larger than in Lake Stechlinsee.
System reconfiguration of hardware resources has been done in multiple system domains. Such systems are usually found in the context of FPGAs, where reconfiguration is done usually over its primitives (e.g., LUTs, Flip-Flops). Or even in the context of MPSoC designs, where core management (e.g., lock-step operation in multi-core designs) is the most used approach. However, recent works have shown that configuration at Functional Units (FUs) granularity might come with benefits. For example, it can increase the configuration space due to its finer granularity, and, as a consequence, the options to deal with problems (e.g., due to aging) in the units itself. Within this context, this paper presents a system capable to configure its FUs (e.g., ALUs, multipliers, dividers) into different operation modes. The system uses an Operating System to control HW reconfiguration during process switching time and takes into account the health state of its units in a mixed-criticality applications scenario. Results show that, within this scenario, the system is able to reconfigure itself accomplishing health state modifications of its HW elements.
The tiny logic elements in modern integrated circuits increase the rate of transient failures significantly. Therefore, redundancy on various levels is necessary to retain reliability. However, for mixed-criticality scenarios, the typical processor designs offer either too little fault-tolerance or too much redundancy for one part of the applications. Amongst others, we specifically address redundant processor internal functional units (FU) to cope with transient errors and support wear leveling. A real-time operating system (RTOS) was extended to control our prototypical hardware platform and, since it can be configured deterministically within few clock cycles, we are able to reconfigure the FUs dynamically, at process switching time, according to the specified critically of the running processes. Our mechanisms were integrated into the Plasma processor and the Plasma-RTOS. With few changes to the original software code, it was, for example, possible to quickly change from fault-detecting to fault-correcting modes of the processor on demand.
Neuroadaptive technology (NAT) utilizes real-time measures of neurophysiological activity within a closed control loop to create intelligent software adaptation. Measures of electrocortical and neurovascular brain activity are quantified to provide a dynamic representation of the psychological state of the user, with respect to cognitions, emotions and motivation. As such, NAT can access unique aspects of human information processing, and human intelligence, which can subsequently be used to enable more versatile and more human-like forms of machine intelligence. Current trends in different scientific fields indicate an increased interest in integrating context-sensitive information from the human brain into Artificial Intelligence. NAT'22, the Neuroadaptive Technology Conference 2022, was intended to bring scientists interested in Physiological Computing, Applied Neurosciences and Passive Brain-Computer Interfaces together with experts from the fields of Artificial Intelligence, Machine Learning and Intelligent Systems. The main goals of the conference were an exchange of research questions and findings from these fields and the identification of common goals and joint ventures in the domain of Neuroadaptive Technology, including: real-time signal processing, unsupervised vs. supervised ML, designing neuroadaptive interaction, explainable AI (XAI), neuroadaptive applications, hybrid AI systems (DL + symbolic AI) for applied neurosciences, ethics of neurotechnology in real world (responsibility for action, security), cloud-based solutions for data management and more.
NAT'22 was held in Lübbenau, near Berlin, and organised by the Society for Neuroadaptive Technology. These Proceedings contain the abstracts of six keynote lectures and a total of 39 submissions in the categories of Brain-Computer Interface & Applications, Ethics & Perspectives, Artificial Intelligence & Machine Learning, and a poster session.
Vortrag “ICESP XIV. International Conference on Electrostatic Precipitation 2016”, Wroclaw, Polen, 19.-23.09.2016
Back corona and dust resistivity are well known topics in electrostatic precipitation. Back corona results from high dust resistivity and occurs when the field strength in the dust layer surpasses a critical value E crit, which is typically found to be in the order of 15 to 30 kV/cm. Besides the resistivity ρ, the current density is the main parameter: E = i ρ < E crit. Hence, possible actions against back corona include a reduction of ρ by dust conditioning, or a reduction of i, for example by pulsed corona operation.
Much work has been devoted to study the dependence of ρ on dust composition, temperature, humidity, adsorption layers and dust layer porosity, and a variety of different set-ups for dust resistivity measurements has been proposed. Even though some authors report a dependence of ρ on current density or field strength resp., dust resistivity is mostly seen as a material property.
However, in measurements on product dusts in the upper resistivity range, we found that dusts show extremely non-ohmic properties:
Most strikingly, resistivity may vary by several orders of magnitude with time.
Also, the experimental arrangement can change the resistivity results by orders of magnitude: When resistivity is measured with the dust layer exposed to a corona discharge (imitating the situation in a real ESP), ρ depends strongly on the layer thickness. Meanwhile the same dust does not show the strong layer thickness dependence when electrodes are placed on both sides of the dust layer, and also time effects are much less prominent.
Additional findings include that dusts that have been exposed to resistivity measurements show a high level of electrostatic charging afterwards.
An interpretation of these results may be found from the theory of semiconductors and electret materials. Accordingly, highly resistive dust layers do not contain mobile electrons. Current transport occurs only after charge carriers (free electrons or holes) have been injected from the electrodes or from a gas discharge adjacent to the surface.
When the injection process is non-symmetric (e.g. with corona discharge), the current transport through the dust layer can be dominated by charge carriers of one polarity, depending on the polarity of the corona. Some of the effects observed in experiment, namely the layer thickness effect and the current density influence, can indeed be ascribed to unipolar injection and space charge limited conduction.
The time effects can mainly be ascribed to the “deep trapping” of the charge carriers, leading to a high level of immobile space charge. As overall space charge is limited, this reduces the level of mobile space charge available for current transport. The space charge also leads to a deformation of the electric field inside the dust layer, and hence influences injection via the Schottky (thermionic field emission) mechanism.
By integrating the mechanisms of charge transport in dielectrics (injection, drift, immobilization, recombination) into the OpenFOAM® simulation package, rather realistic simulations of time-dependent resistivity are possible. The simulations also are helpful to identify the mechanisms responsible for certain types of resistivity behavior.
The ability to fix molecular nitrogen is considered to be a competitive advantage of Nostocales to overcome periods of nitrogen shortage but it is unclear to what extend these cyanobacteria import nitrogen into freshwaters and if they are able to compensate the efforts of reducing anthropogenic nitrogen input.
We studied nitrogen fixation, cyanobacterial biovolume and species composition and abiotic parameters in two polymictic lakes (Germany) over three years. Although Nostocales were present from April to November N2-fixation was found only from June/July to September. In the summer months, it amounted up to 40 mgN m-²d-¹ or up to 500 mgN m-²d-¹ resulting in rather low annual N-inputs between 0.1 and 8 gN m-²a-¹. We found a high variation in N2-fixation rates between the two lakes and the years, which could neither be explained by total Nostocales biovolume nor heterocyte numbers. N2-fixation rates measured in the field will be analyzed on Nostocales species level, be compared to those of laboratory cultures and be discussed in the context of possible phosphorus or light limitation of Nostocales.
The strive for performance, low power consumption, and less chip area have been diminishing the reliability and the time to fault occurrences due to wear out of electronic devices. Recent research has shown that functional units within processors usually execute a different amount of operations when running programs. Therefore, these units present different individual wear out during their lifetime. Most existent schemes for re-configuration of processors due to fault detection and other processor parameters are done at the level of cores which is a costly way to achieve redundancy. This paper presents a low latency (approximately 1 clock cycle) software controlled mechanism to reconfigure units within processor cores according to predefined parameters. Such reconfiguration capability delivers features like wear out balance of processor functional units, configuration of units according to the criticality of tasks running on an operating system and configurations to gain in performance (e.g. parallel execution) when possible. The focus of this paper is to show the implemented low latency reconfiguration mechanism and highlight its possible main features.
This paper investigates the case study of Kilian Ignaz Dientzenhofer’s church of St. Hedwig in the Polish region of Silesia. The building, a popular pilgrimage church, is known in the history of art and architecture as a Late Baroque jewel with a curious design and famous frescoes. While the shape of the building and its vault has led to different interpretations in the past, its geometry has not yet been analysed on a reliable basis. Moreover, the construction of the brick vault has not yet been subject to scientific research. In order to investigate these aspects, a 3D laser scan of the vault’s extrados and intrados was utilised as the primary source. The 3D model generated from the scan not only enabled the detailed description of structural ribs, brick patterns and construction details on the extrados, but also made a geometrical analysis using reverse geometric engineering possible. The results show a geometric design of the vault surfaces as well as double-curved arches based on simple plane circle segments. This clear geometric definition of the vault is associated with a remarkable simplicity of construction method and centering. In the context of other vault designs by members of the Dientzenhofer professional circle of master builders and architects, the vault of St. Hedwig can be seen as both a continuation and an improvement in terms of geometric design and construction details.