Virtualisierung im Future Internet Virtualisierungsmethoden und Anwendungen

Das Future Internet stellt sich der Herausforderung, die Verkn?cherung und die Unzul?nglichkeiten des heutigen Internets zu überwinden. Es soll beispielsweise robust, zuverl?ssig und fehlertolerant sein und dabei Dienste auf energieeffiziente Weise erbringen. Zus?tzlich müssen auch neue Anforderungen antizipiert werden, die zukünftige Dienste und Netze stellen, um der Entwicklung von neuen Diensten und Protokollen nicht im Wege zu stehen. Erforderlich ist hierbei die Entwicklung einer ?u?erst variablen und rekonfigurierbaren Netzwerkarchitektur, die eine m?glichst einfache und autonome Netzwerkverwaltung mit einschlie?t. Die Virtualisierung von Host- und Netzwerkressourcen stellt in diesem Zusammenhang eine der Schlüsseltechnologien dar, mit der diese notwendige Flexibilit?t erreicht werden kann. Virtualisierung verbirgt die Komplexit?t von physikalischen Netzwerkinfrastrukturen und stellt homogene, flexible und dynamisch rekonfigurierbare virtuelle Ressourcen zur Verfügung. Dieser Artikel gibt einen überblick über verschiedene Host- und Netzwerkvirtualisierungsmethoden. An mehreren Beispielen wird aufgezeigt, wie verschiedene Herausforderungen angegangen werden k?nnen, die sowohl im heutigen Internet als auch im Internet der Zukunft eine Rolle spielen.     

Development of a qualitative test method for the cleanability of polymer woven filter media

In this paper a new method for cleaning of filter media is presented, and the cleanability with different textures and surface finishes is compared. With the method described, it is possible to evaluate the quality of the cleaning process. According to the German VDMA standard cleaning test, riboflavin and malt extract are applied as model contaminants for evaluation of the cleaning results. To compare the cleanability of filter media with different properties and geometries the results are adapted to the law of mass transfer and to the Sherwood number, a dimensionless parameter describing the quality of a cleaning process.     

Surface lipids of the social waspPolistes annularis (L.) and its nest and nest pedicel

Cuticular lipids were recovered fromPolistes annularis workers and characterized by combined gas-chromatography-mass spectrometry. These lipids were found to be straight-chain and methyl-branched hydrocarbons with the major components being 13,17-dimethylhentriacontane (18%), 3-methyl-nonacosane (13%), and 3-methylheptacosane (11%). Cuticular lipids with a very similar composition were found on the surface of the larvae, eggs, and adult males ofPolistes annularis as well as on the surface of the nest and nest pedicel of the wasp. Hexadecanoic acid and octadecenoic acid were also found on the surface of the nest pedicel and these acids and/or the hydrocarbons may play a defensive role for the wasps.     

Polystyrol und styrolcopolymere

Polystyrene is with a present day sales volume of 8,5 million tons a year one of the most important thermoplastics worldwide. Its unique property profile makes polystyrene an ideal material for housings, refrigerator inliners and demanding packaging applications, when transparency and/or surface quality as well as stiffness are important. Its economic success is due to its favourable price/performance ratio and also not least to its excellent processability as an amorphous material. In this contribution the versatility and potential for innovation of polystyrene and its copolymers are discussed. Using standard and impact modified polystyrene, it is shown how the maturity of the polymerisation process, the broad spectrum of product modifications as well as processing know how of this class of materials have helped to promote the breakthrough of this product to an acknowledged plastic material. Modern polystyrene variations are increasingly meeting the special property requirements of other materials, like for example high heat resistant PPE/PS-I blends, weather resistant ASA and AES plastics, tough and crystal clear star polymers or hydrogenated and unhydrogenated elastomers. A special feature of polystyrene is that it is one of the few monomers which can be polymerised using all the known methods for vinyl monomers to produce high molecular weight products. Thus the newest polymerisation techniques using metallocene catalysed and anionic polymerisation methods lead to products with the property profile of engineering plastics. Polystyrene will continue to grow in the future and thus increase in importance, especially while it can be easily depolymerised and in the form of styrene monomer recycled.     

The TTA's Approach to Resilience after Transient Upsets

The Time-Triggered Architecture, as architecture for safety-critical real-time applications, incorporates fault-tolerance mechanisms to ensure correct system operation despite failures. The primary fault hypothesis of the TTA claims to tolerate either the arbitrary failure of any one of its nodes or the passively arbitrary failure of any one of its communication channels. To cover these failure modes, active redundancy techniques are used, which basically means that nodes and channels are physically replicated. The primary fault hypothesis, is, however, not strong enough for certain applications that have to tolerate transient upsets of multiple, possibly all, components in the system. Such a transient upset of the system may break up the synchrony of the nodes and leave disjoined sets of nodes synchronized to each other while the overall synchronization is lost. Although the TTA provides a clique avoidance algorithm that is able to correct a wide class of such multiple transient failures, a stronger algorithm is needed for full coverage. In this paper we discuss a secondary fault hypothesis for the TTA that addresses the transient upset of multiple components and present a new clique resolving algorithm based on the TTA's integrated diagnosis and startup service. This paper is a revised version of Steiner et al. (2003). This work has been funded by the European Project DECOS (Project number: IST-511764). Michael Paulitsch is currently affiliated with Honeywell International.     

Relation between intracarotid amobarbital memory asymmetry scores and hippocampal sclerosis in patients undergoing anterior temporal lobe resections

The intracarotid amobarbital procedure (IAP) is used to evaluate memory function preoperatively in candidates for anterior temporal lobe resections (ATL). We examined IAP memory asymmetry scores in 30 patients undergoing ATL (17 R, 13 L), as a function of the presence (HS+) or absence (HS-) of hippocampal sclerosis. Ictal onset zones were determined by extraoperative recording with subdural strip electrodes in all but 3 patients in whom magnetic resonance imaging (MRI) scan showed HS. MRI scans were otherwise normal. All patients were left hemisphere dominant for language except 1, in whom language was represented bilaterally. IAP memory testing involved presentation of eight subjects during anesthesia of each hemisphere, followed by recognition testing after patients recovered from amobarbital effects. A score of 1 was given for each correctly recognized object, and 0.5 was deducted for each false-positive identification. There were 16 foils. A total asymmetry score was calculated, which was positive if there was agreement between the direction of the symmetry and side of operation and negative if reversed. The mean asymmetry score for HS- (n = 8) was 0.9; that for HS+ (n = 22) was 4.1 (p < 0.01). IAP memory performance provided lateralizing information (asymmetry score > or = + or -2) in 73% of cases; among these, the lateralization was correct in 91%. Our data indicate that IAP memory asymmetry predicts both laterality of ictal onset and the presence of HS.     

Internal Friction in Lithium Aluminosilicate Glass-Ceramics

This paper describes the results of an investigation of the anelastic behavior of two glass-ceramic materials with similar compositions, one nucleated with TiO₂ and the other with ZrO₂. The influence of the grain size, residual glass fraction, and composition was examined. A low-frequency torsion pendulum was constructed for this purpose. The as-received TiO₂-nucleated. Corning Code 9608 ceramic exhibits an attenuation peak at about 750°C; when heat-treated at 1200°C for 167 h, the attenuation peaks at approximately 850°C. The ZrO nucleated glass-ceramic showed no such peak. Our results indicate that this anelastic behavior is due to grain boundary sliding, but the rates and magnitude of sliding are strongly dependent on boundary chemistry.