Services for numerical simulations and optimisations in grids

Numerical simulations are typically very computer intensive. A way to satisfy the arising demands for compute power is the employment of grid technology. But today, there exist only a few tools supporting the user in using grids for numerical simulations. In addition, some basic problems of grid technology are not solved with satisfaction. The goal of the project OptiNum-Grid was to address these issues. We present a number of tools that were developed in the project. These are tools for parameter sweeps and optimisations in grids, for data security and automatic software installation, as well as for virtual environments in grids. The tools were evaluated in the context of three different use cases, namely finite element method simulations, analog circuit simulations and e-beam simulations.     

Genetic analysis of new progesterone-based fertility traits in dairy cows measured on-farm

The objectives of this study were (1) to analyze the agreement of a standard laboratory ELISA for progesterone (P4) with an automated on-farm ELISA kit operated under commercial conditions in 1,297 milk samples from 50 dairy cows; (2) to study the influence of the method of detection of luteal activity on genetic parameters of fertility traits based on P4 measured with an automated on-farm ELISA once weekly from wk 3 to 9 postpartum in the milk of 1,304 cows; and (3) to study the influence of sampling frequency (once or twice weekly from wk 3 to 9) on the same traits from 296 cows. Luteal activity can be detected when there is an active corpus luteum in the ovary producing P4 and indicating the onset of reproductive cyclicity after calving. The on-farm ELISA overestimated P4 contents by a mean square error of prediction of 2.76 ng/mL and had an intermediate Spearman correlation with the laboratory kit (0.54). For the second objective, the postpartum interval to the commencement of luteal activity (C-LA), proportion of luteal activity between d 15 and 63 postpartum (P-LA), calculated as the number of samples above the threshold for high P4 values divided by the number of all samples, and delay of first ovulation (DOV1), defined as C-LA occurring later than d 45 postpartum, were derived from the P4 profiles. Both C-LA and DOV1 were determined by (a) thorough qualitative visual inspection of the profile, (b) the profile's mean as threshold for the first increase in P4 postpartum, indicating commencement of luteal activity, and (c) 3 ng/mL as threshold for the first increase in P4, a value that has been used by many other studies. Similarly, P-LA was determined by using methods (b) and (c). Estimates of heritability were 0.04 to 0.13 for C-LA, 0.12 to 0.23 for P-LA, and 0.03 to 0.07 for DOV1. Genetic correlation of P-LA with C-LA and with the profile's mean P4 was ?1.00. The profile's mean had a higher estimate of heritability (0.11–0.12) than C-LA or DOV1. It can be calculated as the arithmetic mean of all P4 values of a profile, whereas C-LA, P-LA, and DOV1 need a definition of a threshold for high P4 values. We therefore suggest the profile's mean as a promising candidate for further research. For the third objective, once-weekly sampling was mimicked by neglecting every second sample, and C-LA and DOV1 shifted toward a later onset of cyclicity. Thus, a common standard for sampling regimen and detection algorithm is essential to avoid incompatibility between studies.     

Sicherheitskern(e) für Smartphones: Ansätze und Lösungen

Dieser Artikel beschreibt die verschiedenen, heute verfolgten theoretischen und praktischen L?sungsans?tze zur Trennung von Informationen aus unterschiedlichen Sicherheitsstufen. Ein typisches Anwendungsziel ist beispielswiese die Verwendung eines einzelnen Smartphones für die berufliche und private Nutzung.     

Benefiting from users’ gaze: selection of image regions from eye tracking information for provided tags

Providing image annotations is a tedious task. This becomes even more cumbersome when objects shall be annotated in the images. Such region-based annotations can be used in various ways like similarity search or as training set in automatic object detection. We investigate the principle idea of finding objects in images by looking at gaze paths from users, viewing images with an interest in a specific object. We have analyzed 799 gaze paths from 30 subjects viewing image-tag-pairs with the task to decide whether a tag could be found in the image or not. We have compared 13 different fixation measures analyzing the gaze paths. The best performing fixation measure is able to correctly assign a tag to a region for 63 % of the image-tag-pairs and significantly outperforms three baselines. We look into details of the image region characteristics such as the position and size for incorrect and correct assignments. The influence of aggregating multiple gaze paths from several subjects with respect to improving the precision of identifying the correct regions is also investigated. In addition, we look into the possibilities of discriminating different regions in the same image. Here, we are able to correctly identify two regions in the same image from different primings with an accuracy of 38 %.     

穿越迷雾,秀外慧中

英国美学家克莱夫·贝尔在《艺术》中提有意味的形式是一切艺术的共同本质。再看看如今的建筑设计,每一个业主都希望他的新建筑具有特立独行的外观风格,以标榜自己对时代感的把握和独特的审美品味。特别是近年来,在世界上一些高速     

An extended procedure for convective boundary conditions on transient thermal simulations of machine tools

The need of reliable structural properties of machine tools in the development phase are becoming increasingly important due to mounting accuracy demands and shrinking development periods. The finite element method is the most established tool applied in this context. Currently, calculating thermal properties and compensation of thermally caused shifts are mainly the focus of simulation studies due to high performance and the usage of dry processing. The accuracy with which thermal properties can be mapped today is measurably lower than current static and dynamic properties. The reason is due to strong interaction of the specific physical effects and the complexity of pertinent constraints. With constrained parameters the impact caused is defining the convective heat transmission. The heat transmission coefficient can be calculated analytically or numerically. This article is presenting a method that allows permanent adaptation of this coefficient to make it possible to better apply convective heat transmission to time-variable thermal simulations especially for mechanical based finite element models.     

Cluster analysis of dynamic cerebral contrast-enhanced perfusion MRI time-series

We performed neural network clustering on dynamic contrast-enhanced perfusion magnetic resonance imaging time-series in patients with and without stroke. Minimal-free-energy vector quantization, self-organizing maps, and fuzzy c-means clustering enabled self-organized data-driven segmentation with respect to fine-grained differences of signal amplitude and dynamics, thus identifying asymmetries and local abnormalities of brain perfusion. We conclude that clustering is a useful extension to conventional perfusion parameter maps.