Cloud computing services: taxonomy and comparison

Cloud computing is a highly discussed topic in the technical and economic world, and many of the big players of the software industry have entered the development of cloud services. Several companies what to explore the possibilities and benefits of incorporating such cloud computing services in their business, as well as the possibilities to offer own cloud services. However, with the amount of cloud computing services increasing quickly, the need for a taxonomy framework rises. This paper examines the available cloud computing services and identifies and explains their main characteristics. Next, this paper organizes these characteristics and proposes a tree-structured taxonomy. This taxonomy allows quick classifications of the different cloud computing services and makes it easier to compare them. Based on existing taxonomies, this taxonomy provides more detailed characteristics and hierarchies. Additionally, the taxonomy offers a common terminology and baseline information for easy communication. Finally, the taxonomy is explained and verified using existing cloud services as examples

On the distribution of Astrobunus laevipes CANESTRINI, 1872 (Arachnida: Opiliones) in Central Europe

Published data and unpublished communications show that the range of Astrobunus laevipes in Central Europe is much larger than previously believed. The present review extends the list of records to the German states of Baden-Württemberg, Hessia, Rhineland Palatinate, Bavaria, Northrhine-Westfalia, Saxony, and Lower Saxony and provides a map of the present distribution in Germany. Furthermore, it lists new findings of A. laevipes in the Czech Republic and Hungary (Rakaca/Serehat Valley). Records of A. laevipes in Austria are not included in this review

Resolubility of Image-Potential Resonances

A theory of image-potential states is presented for the general case where these surface electronic states are resonant with a bulk continuum. The theory extends the multiple scattering approach of Echenique and Pendry into the strong coupling regime while retaining independence from specific forms of surface and bulk potentials. The theory predicts the existence of a well-resolved series of resonances for arbitrary coupling strengths. Surprisingly, distinct image-potential resonances are thus expected to exist on almost any metal surface, even in the limiting case of jellium