TY - JOUR A1 - Lorenz, Claas A1 - Clemens, Vera Elisabeth A1 - Schrötter, Max A1 - Schnor, Bettina T1 - Continuous verification of network security compliance JF - IEEE transactions on network and service management N2 - Continuous verification of network security compliance is an accepted need. Especially, the analysis of stateful packet filters plays a central role for network security in practice. But the few existing tools which support the analysis of stateful packet filters are based on general applicable formal methods like Satifiability Modulo Theories (SMT) or theorem prover and show runtimes in the order of minutes to hours making them unsuitable for continuous compliance verification. In this work, we address these challenges and present the concept of state shell interweaving to transform a stateful firewall rule set into a stateless rule set. This allows us to reuse any fast domain specific engine from the field of data plane verification tools leveraging smart, very fast, and domain specialized data structures and algorithms including Header Space Analysis (HSA). First, we introduce the formal language FPL that enables a high-level human-understandable specification of the desired state of network security. Second, we demonstrate the instantiation of a compliance process using a verification framework that analyzes the configuration of complex networks and devices - including stateful firewalls - for compliance with FPL policies. Our evaluation results show the scalability of the presented approach for the well known Internet2 and Stanford benchmarks as well as for large firewall rule sets where it outscales state-of-the-art tools by a factor of over 41. KW - Security KW - Tools KW - Network security KW - Engines KW - Benchmark testing; KW - Analytical models KW - Scalability KW - Network KW - security KW - compliance KW - formal KW - verification Y1 - 2021 U6 - https://doi.org/10.1109/TNSM.2021.3130290 SN - 1932-4537 VL - 19 IS - 2 SP - 1729 EP - 1745 PB - Institute of Electrical and Electronics Engineers CY - New York ER - TY - JOUR A1 - Intziegianni, Konstantina A1 - Cassel, Michael A1 - Rauf, S. A1 - White, S. A1 - Rector, Michael V. A1 - Kaplick, Hannes A1 - Wahmkow, Gunnar A1 - Kratzenstein, S. A1 - Mayer, Frank T1 - Influence of Age and Pathology on Achilles Tendon Properties During a Single-leg Jump JF - International journal of sports medicine N2 - Prevalence of Achilles tendinopathy increases with age leading to a weaker tendon with predisposition to rupture. Conclusive evidence of the influence of age and pathology on Achilles tendon (AT) properties remains limited, as previous studies are based on standardized isometric conditions. The study investigates the influence of age and pathology on AT properties during single-leg vertical jump (SLVJ). 10 children (C), 10 asymptomatic adults (A), and 10 tendinopathic patients (T) were included. AT elongation [mm] from rest to maximal displacement during a SLVJ on a force-plate was sonographically assessed. AT compliance [mm/N]) and strain [%] was calculated by dividing elongation by peak ground reaction force [N] and length, respectively. One-way ANOVA followed by Bonferroni post-hoc correction (=0.05) were used to compare C with A and A with T. AT elongation (p=0.004), compliance (p=0.001), and strain were found to be statistically significant higher in C (27 +/- 3mm, 0.026 +/- 0.006[mm/N], 13 +/- 2%) compared to A (21 +/- 4mm, 0.017 +/- 0.005[mm/N], 10 +/- 2%). No statistically significant differences (p0.05) was found between A and T (25 +/- 5mm, 0.019 +/- 0.004[mm/N], 12 +/- 3%). During SLVJ, tendon responded differently in regards to age and pathology with children having the most compliant AT. Higher compliance found in healthy tendons might be considered as a protective factor against load-related injuries. KW - children KW - tendinopathy KW - compliance KW - dynamic KW - ultrasonography Y1 - 2016 U6 - https://doi.org/10.1055/s-0042-108198 SN - 0172-4622 SN - 1439-3964 VL - 37 SP - 973 EP - 978 PB - Thieme CY - Stuttgart ER -