Preventing Distributed Denial-of-Service Attacks on the IMS Emergency Services Support through Adaptive Firewall Pinholing

Emergency services are vital services that Next Generation Networks (NGNs) have to provide. As the IP Multimedia Subsystem (IMS) is in the heart of NGNs, 3GPP has carried the burden of specifying a standardized IMS-based emergency services framework. Unfortunately, like any other IP-based standards, the IMS-based emergency service framework is prone to Distributed Denial of Service (DDoS) attacks. We propose in this work, a simple but efficient solution that can prevent certain types of such attacks by creating firewall pinholes that regular clients will surely be able to pass in contrast to the attackers clients. Our solution was implemented, tested in an appropriate testbed, and its efficiency was proven.Comment: 17 Pages, IJNGN Journa

Mass Taxon-Sampling as a Strategy towards Illuminating the Natural History of Campanula (Campanuloideae)

Speciose clades usually harbor species with a broad spectrum of adaptive strategies and complex distribution patterns, and thus constitute ideal systems to disentangle biotic and abiotic causes underlying species diversification. The delimitation of such study systems to test evolutionary hypotheses is difficult because they often rely on artificial genus concepts as starting points. One of the most prominent examples is the bellflower genus Campanula with some 420 species, but up to 600 species when including all lineages to which Campanula is paraphyletic. We generated a large alignment of petD group II intron sequences to include more than 70% of described species as a reference. By comparison with partial data sets we could then assess the impact of selective taxon sampling strategies on phylogenetic reconstruction and subsequent evolutionary conclusions

Impact of the Scheduling Strategy in Heterogeneous Systems That Provide Co-Scheduling

ABSTRACT In recent years, the number of processing units per compute node has been increasing. In order to utilize all or most of the available resources of a high-performance computing cluster, at least some of its nodes will have to be shared by several applications at the same time. Yet, even if jobs are co-scheduled on a node, it can happen that high performance resources remain idle, although there are jobs that could make use of them (e. g. if the resource was temporarily blocked when the job was started). Heterogeneous schedulers, which schedule tasks for different devices, can bind jobs to resources in a way that can significantly reduce the idle time. Typically, those schedulers make their decisions based on a static strategy. In this paper, we investigate the impact if a heterogeneous scheduler allows modifications of the strategies at runtime. For a set of applications, we determine the makespan and show how it is influenced by four different scheduling strategies. A well-chosen strategy can result in a speedup of more the 2.5 in comparison to other strategies

Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation

OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (

Highly Available DHTs: Keeping Data

The research in the paper is motivated by building a decentralized /P2P XML storage on top of a DHT (Distributed Hash Table)

Strategien zum Erstellen von Sauberkeitsgrenzwerten: Technische Sauberkeit in der Automobilindustrie. Seminar, 26. Februar 2019, Stuttgart

Die Technische Sauberkeit ist heute ein etabliertes Qualitätsmerkmal in der Automobilbranche. Dabei stehen Entwickler immer wieder vor der Herausforderung valide und wirtschaftlich vertretbare Sauberkeitsgrenzwerte festzulegen. Bislang fehlen jedoch anerkannte Methoden, an denen sich Entwickler orientieren können. Hilfestellung soll diese Fachtagung bieten. Mit einem diversifizierten Programm aus Berechnungs-, Simulations- und Versuchsansätzen soll der Blick über den Tellerrand gerichtet werden, um daraus neue Impulse und Lösungsansätze zu realisieren. Gleichzeitig bietet diese Veranstaltung ein Forum für Experten, um sich über aktuelle und zukünftige Trends und Entwicklungen auszutauschen