Generalization of form in visual pattern classification.

Human observers were trained to criterion in classifying compound Gabor signals with sym- metry relationships, and were then tested with each of 18 blob-only versions of the learning set. General- ization to dark-only and light-only blob versions of the learning signals, as well as to dark-and-light blob versions was found to be excellent, thus implying virtually perfect generalization of the ability to classify mirror-image signals. The hypothesis that the learning signals are internally represented in terms of a 'blob code' with explicit labelling of contrast polarities was tested by predicting observed generalization behaviour in terms of various types of signal representations (pixelwise, Laplacian pyramid, curvature pyramid, ON/OFF, local maxima of Laplacian and curvature operators) and a minimum-distance rule. Most representations could explain generalization for dark-only and light-only blob patterns but not for the high-thresholded versions thereof. This led to the proposal of a structure-oriented blob-code. Whether such a code could be used in conjunction with simple classifiers or should be transformed into a propo- sitional scheme of representation operated upon by a rule-based classification process remains an open question

Multi-level Monte Carlo Finite Element method for elliptic PDEs with stochastic coefficients

In Monte Carlo methods quadrupling the sample size halves the error. In simulations of stochastic partial differential equations (SPDEs), the total work is the sample size times the solution cost of an instance of the partial differential equation. A Multi-level Monte Carlo method is introduced which allows, in certain cases, to reduce the overall work to that of the discretization of one instance of the deterministic PDE. The model problem is an elliptic equation with stochastic coefficients. Multi-level Monte Carlo errors and work estimates are given both for the mean of the solutions and for higher moments. The overall complexity of computing mean fields as well as k-point correlations of the random solution is proved to be of log-linear complexity in the number of unknowns of a single Multi-level solve of the deterministic elliptic problem. Numerical examples complete the theoretical analysi

Multilevel Monte Carlo method for parabolic stochastic partial differential equations

We analyze the convergence and complexity of multilevel Monte Carlo discretizations of a class of abstract stochastic, parabolic equations driven by square integrable martingales. We show under low regularity assumptions on the solution that the judicious combination of low order Galerkin discretizations in space and an Euler-Maruyama discretization in time yields mean square convergence of order one in space and of order1/2 in time to the expected value of the mild solution. The complexity of the multilevel estimator is shown to scale log-linearly with respect to the corresponding work to generate a single path of the solution on the finest mesh, resp. of the corresponding deterministic parabolic problem on the finest mes

Temperature- and Field Dependent Characterization of a Twisted Stacked-Tape Cable

The Twisted Stacked-Tape Cable (TSTC) is one of the major high temperature superconductor cable concepts combining scalability, ease of fabrication and high current density making it a possible candidate as conductor for large scale magnets. To simulate the boundary conditions of such a magnets as well as the temperature dependence of Twisted Stacked-Tape Cables a 1.16 m long sample consisting of 40, 4 mm wide SuperPower REBCO tapes is characterized using the "FBI" (force - field - current) superconductor test facility of the Institute for Technical Physics (ITEP) of the Karlsruhe Institute of Technology (KIT). In a first step, the magnetic background field is cycled while measuring the current carrying capabilities to determine the impact of Lorentz forces on the TSTC sample performance. In the first field cycle, the critical current of the TSTC sample is tested up to 12 T. A significant Lorentz force of up to 65.6 kN/m at the maximal magnetic background field of 12 T result in a 11.8 % irreversible degradation of the current carrying capabilities. The degradation saturates (critical cable current of 5.46 kA at 4.2 K and 12 T background field) and does not increase in following field cycles. In a second step, the sample is characterized at different background fields (4-12 T) and surface temperatures (4.2-37.8 K) utilizing the variable temperature insert of the "FBI" test facility. In a third step, the performance along the length of the sample is determined at 77 K, self-field. A 15 % degradation is obtained for the central part of the sample which was within the high field region of the magnet during the in-field measurements

Die Wirksamkeit der Kapillarsperre als Deponieoberflächenabdichtung

The principles of capillary barriers are well known from many laboratory studies. A limited number of large-scale applications are known, in particular for the sealing of past pollution and demolition waste. This study investigates the suitability of a capillary barrier for the sealing of a municipal landfill. Laboratory tests have shown the fundamental applicability of the selected materials. The sealing effect of the material combination as a capillary barrier was examined in a large scale tipping trough under step increasing hydraulic load and two differential slopes. The materials showed drain capacities suitable for an effective capillary barrier. For a long-term study under natural weather conditions, two experimental fields with integrated large scale lysimeters and slopes of 10 % and 26 % have been constructed on site at the landfill. The lysimeter data of three subsequent years were used for the analysis. After the growth of a closed cover of vegetation the surface runoff was negligible. Only in wet years it exceeded 2 % of the annual precipitation. In 2000 and 2001 the evapotranspiration was between 55 % and 65 %. In the very wet year 2002, however, it was significantly below 50 %. The predominant part of the lysimeter runoff was drained by the capillary layer. Only heavy precipitation caused a relevant drain into the capillary block. Except for the very wet year 2002 the effectiveness of the whole system exceeded 95 % of the annual precipitation. As expected the efficiency of the steeper lysimeter clearly surpassed 95 %. In order to verify the possibility to reduce the effort for the experimental determination of the efficacy of the capillary barrier by numerical simulations, it was tried to calculate the measured results by numerical models for the water balance layer and the capillary barrier. The results show that in principle a realistic prediction is possible. However, a reliable prediction of the measured results can only be achieved by using parameters that were calculated by inverse modeling for the unsaturated hydraulic conductivity. Because of the high sensitivity of the model, calculations with parameters predicted by standard methods did not lead to plausible results, but overestimated the effectiveness of the capillary barrier. Therefore it is not advised to substitute large scale tipping experiments by numerical modeling. Although the capillary barrier is not gas proof, the closed water coating above the boundary to the capillary block largely restricts the movement of gas. Laboratory experiments resulted in very low permeability for gas through an aqueous capillary barrier. Measurements at the experimental fields showed that the capillary barrier significantly reduces the emission of gas at the surface compared to the non-sealed landfill surface. However, under adverse air pressure conditions low gas emissions are still measurable. Considering the present investigations, the capillary barrier is a competitive and secure alternative especially for the fracture-prone clay liner. For demolition waste it can be used as single sealing. For municipal waste, as in the underlying landfill of Bayreuth, the combination with an additional sealing element, e. g. a synthetic liner is recommended.Die grundsätzliche Wirkungsweise der Kapillarsperre ist bereits aus zahlreichen Laborversuchen bekannt. Darüber hinaus gibt es auch schon praktische Anwendungen, vor allem zur Abdichtung von Altlasten und Bauschuttdeponien. In der vorliegenden Arbeit wurde die Eignung der Kapillarsperre zur Oberflächenabdichtung einer Hausmülldeponie untersucht. Nachdem durch Laboruntersuchungen die prinzipielle Eignung der ausgewählten Materialien bestätigt wurde, erfolgte die Prüfung der Kapillarsperrenwirkung der Materialkombination anhand mehrwöchiger Großrinnenversuche mit stufenförmig gesteigerter Belastung und zwei unterschiedlichen Neigungen. Die daraus resultierenden Dränkapazitäten zeigten, dass die ausgewählte Materialkombination über wirksame Kapillarsperreneigenschaften verfügt. Für die Langzeituntersuchung unter natürlichen Witterungsverhältnissen wurden auf der Deponie Bayreuth unter baupraktischen Bedingungen zwei Versuchsfelder mit integrierten Großlysimetern mit Hangneigungen von 10 % und 26 % errichtet. Für die Auswertung der Lysimeterabflüsse standen drei Messjahre zur Verfügung. Der Oberflächenabfluss war nach der Ausbildung einer durchgehenden Pflanzendecke vernachlässigbar. Er überschritt nur bei überdurchschnittlichen Niederschlagsjahren 2 % des gesamten Jahresniederschlages. Die Evapotranspiration lag in den Jahren 2000 und 2001 zwischen 55 % und 65 %. Im sehr niederschlagsreichen Jahr 2002 sank sie allerdings erheblich unter 50 %. Der überwiegende Teil der Lysimeterabflüsse wurde von der Kapillarschicht abgeführt. Lediglich bei sehr starken Niederschlagsereignissen traten auch im Kapillarblock nennenswerte Abflussmengen auf. Der Wirkungsgrad des Gesamtsystems übertraf, abgesehen vom flachen Versuchsfeld im sehr niederschlagsreichen Messjahr 2002, immer 95 % des Jahresniederschlages. Der Wirkungsgrad des steilen Versuchsfeldes betrug erwartungsgemäß noch deutlich mehr als 95 %. Um zu prüfen, ob sich der versuchstechnische Aufwand für die Bestimmung der Effektivität einer Kapillarsperre durch numerische Simulationen verringern lässt, wurde versucht die gemessenen Ergebnisse mit Simulationsmodellen für die Wasserhaushaltsschicht und die Kapillarsperre nachzurechnen. Die Ergebnisse zeigen, dass eine realitätsnahe Simulation grundsätzlich möglich ist. Die Messergebnisse waren jedoch nur mit durch inverse Modellierung bestimmten Parametern für die ungesättigte hydraulische Leitfähigkeit zuverlässig vorhersagbar. Aufgrund der großen Sensitivität der Modelle führten Berechnungen mit durch Standardmethoden bestimmten Parametern zu unplausiblen Ergebnissen. Die Effektivität der Kapillarsperre wurde damit überschätzt. Von einem Verzicht auf Großrinnenversuche zugunsten der numerischen Modellierung muss deshalb abgeraten werden. Obwohl die Kapillarsperre an sich nicht gasdicht ist, kann durch den zusammenhängenden Wasserfilm über der Grenze zum Kapillarblock die Gaswegsamkeit stark eingeschränkt werden. In Laborversuchen wurde gezeigt, dass die Gasdurchlässigkeit in einer wasserführenden Kapillarsperre gering ist. Gasmessungen auf den Versuchsfeldern ergaben, dass die Entgasung an der Oberfläche im Vergleich zu den nicht mit der Kapillarsperre abgedeckten Bereichen erheblich reduziert wurde. Geringe Deponiegasaustritte sind jedoch, vor allem unter ungünstigen Luftdruckeinwirkungen, noch messbar. Nach den vorliegenden Untersuchungen ist die Kapillarsperre als kostengünstige und sichere Alternative, vor allem für die unter Umständen rissempfindliche mineralische Abdichtung gut geeignet. Für Deponieklasse I kann sie als einfaches Dichtungssystem eingesetzt werden. Für Deponieklasse II, wie sie in der untersuchten Deponie Bayreuth vorliegt, wird die Kombination mit einem weiteren Dichtungselement, z. B. einer Kunststoffdichtungsbahn, empfohlen

Status quo der kuhgebundenen Kälberaufzucht in Norddeutschland

Die Trennung von Kuh und Kalb innerhalb von 24 Stunden nach der Geburt ist eine gängige Praxis in der Milchviehhaltung. Als Alternative gilt die in der Milchviehhaltung bisher wenig verbreitete Aufzucht der Kälber an der Mutter bzw. einer Ammenkuh. Über die genaue Methodik der Haltung sowie die Vermarktungsstrategien dieser Betriebe ist allerdings wenig bekannt. Deshalb gehen wir diesen Fragen nach. Dafür identifizieren wir in Norddeutschland Betriebe mit kuhgebundenen Kälberaufzuchtsystemen und befragen diese hinsichtlich ihres Betriebsmanagements und ihrer Vermarktungsstrategien

Investigating AHL-lipid bilayer interactions using nonlinear optical spectroscopy

Acylated homoserine lactones (AHLs) play an important role in bacterial infection and biofilm formation and also allow communication between microorganisms and their eukaryotic host cells (Inter-kingdom signaling). The detailed mechanism of these interactions is yet unknown. To mimic interactions between AHLs and cell membranes, the incorporation of AHLs with different chain lengths in supported lipid bi- layers (SLBs) was studied using vibrational sum-frequency generation (SFG) spectroscopy. Deuterium- labelled AHLs were synthesized to prevent the overlap of spectroscopic bands allowing the detailed analysis of the interaction. Three AHLs of different chain length were investigated and their orienta- tion within the lipid bilayer was determined. Moreover, the development of AHL-related SFG signals over 5 h was studied providing evidence that AHLs can cross the bilayer in a flip-flop process. However, the determined half life of this process is of the order of days indicating that it is not relevant for the signaling in bacterial biofilms. Furthermore, to relate structural changes with terminal groups and chain lengths, differently ter- minated self-assembled monolayers (SAMs) were studied with SFG spectroscopy in air and in situ. Pyridine-terminated SAMs present a different behavior upon electrochemical desorption depending on an odd or even numbered aliphatic chain. Using SFG spectroscopy it was determined that even numbered pyridine-terminated self-assembled monolayers retain their structure, whereas odd numbered monolayers lose their conformation upon desorption. Furthermore, nonlinear third-order effects were observed with this experimental setup and could be readily explained with theoretical predictions

Motivation, Mindset, and Grading Systems

This action research study examines whether students in a standards-based grading environment are more intrinsically motivated than students in traditional grading environment. Additionally, it examines whether students in a standards-based grading environment exhibit more of a fixed or growth mindset compared to students in a traditional grading environment. The participants were 72 sixth grade students in a standards-based grading classroom environment, and 32 students in a traditional grading-based classroom environment. A survey with statements reflecting students’ intrinsic motivation, extrinsic motivation, fixed mindset, and growth mindset was administered to both groups of students. The survey results suggest that the grading environment, standards-based or traditional, does not account for students’ levels of intrinsic and extrinsic motivation, nor does it predict whether a student has a fixed or growth mindset