317 research outputs found
Security Mechanisms of wireless Building Automation Systems
This paper describes the security mechanisms of several wireless building automation technologies, namely ZigBee, EnOcean, ZWave, KNX, FS20, and Home-Matic. It is shown that none of the technologies provides the necessary measure ofsecurity that should be expected in building automation systems. One of the conclusions drawn is that software embedded in systems that are build for a lifetime of twenty years or more needs to be updatable
Recommended from our members
Wave trains, solitons and modulation theory in FPU chains
We present an overview of recent results concerning wave trains,
solitons and their modulation in FPU chains. We take a thermodynamic
perspective and use hyperbolic scaling of particle index and time in order to
pass to a macroscopic continuum limit. While strong convergence yields the
well-known p-system of mass and momentum conservation, we generally obtain a
weak form of it in terms of Young measures. The modulation approach accounts
for microscopic oscillations, which we interpret as temperature, causing
convergence only in a weak, average sense. We present the arising Whitham
modulation equations in a thermodynamic form, as well as analytic and
numerical tools for the resolution of the modulated wave trains. As a
prototype for the occurrence of temperature from oscillation-free initial
data, we discuss various Riemann problems, and the arising dispersive shock
fans, which replace Lax-shocks. We predict scaling and jump conditions
assuming a generic soliton at the shock front
Wave trains, solitons and modulation theory in FPU chains
We present an overview of recent results concerning wave trains, solitons and their modulation in FPU chains. We take a thermodynamic perspective and use hyperbolic scaling of particle index and time in order to pass to a macroscopic continuum limit. While strong convergence yields the well-known p-system of mass and momentum conservation, we generally obtain a weak form of it in terms of Young measures. The modulation approach accounts for microscopic oscillations, which we interpret as temperature, causing convergence only in a weak, average sense. We present the arising Whitham modulation equations in a thermodynamic form, as well as analytic and numerical tools for the resolution of the modulated wave trains. As a prototype for the occurrence of temperature from oscillation-free initial data, we discuss various Riemann problems, and the arising dispersive shock fans, which replace Lax-shocks. We predict scaling and jump conditions assuming a generic soliton at the shock front
Gefäßversuch zur Wirkung von Biokohle-Substraten mit unterschiedlichen Kohlegehalten auf Eigenschaften ertragsschwacher Acker- und Kippböden der Lausitz
Mit dem vorliegenden Beitrag sollen die pflanzenbaulichen Effekte insbesondere die Düngewirkung der Biokohle-Substrate (BKS) auf ertragsschwache Böden aus der Lausitz aufgezeigt werden. In einem Versuch mit Mitscherlich-Gefäßen wurden einem Ackerboden (Z) (Bodenart Su3) und einem Kipprohboden (W) (Bodenart Sl2) stufenweise 30 bis 240 t TS ha-1 BKS mit einem Biokohle-Anteil von 15 (BKS15) bzw. 30 Vol.-% (BKS30) appliziert. Als Testkultur diente Knaulgras (Dactylis glomerata L.).
Nach einer Versuchsdauer von einem Jahr wurden Bodenproben entnommen und auf ihre chemischen und physikalischen Eigenschaften untersucht. Der Einsatz der BKS führte teilweise zu einer Verbesserung des Wasser- und Nähr-stoffhaushaltes in Abhängigkeit von den Ausgangsbedingungen der verwendeten Böden
Auswirkungen von Biokohlesubstrat-Gaben zu ertragsschwachen Ackerböden auf das Sickerwasser und die Nährstofffrachten in einem vierjährigen Lysimeterversuch
Um die Effekte von Biokohle-Substraten (BKS) auf Menge und Qualität der Sickerwässer ertragsschwacher Ackerböden zu untersuchen, wurden Lysimeterversuche mit einem Kipprohboden und einer Podsol-Braunerde angelegt. Bei der Podsol-Braunerde aus Sand kam es nach Gabe von 90 t BKS ha-1 im Vergleich mit reiner Mineraldüngung zu einem Nährstoffüberangebot und verstärkter N- und K-Auswaschung. In dem humus- und nährstoffarmen Kippboden führte die BKS-Gabe zu verbessertem Pflanzenwachstum und geringerer Sickerwasserbildung ab dem zweiten Jahr. Die N- und K-Austräge wurden reduziert. Für die Rekultivierung von Kippböden stellt der Einsatz von BKS somit eine vielversprechende Option dar
Nonequilibrium control of thermal and mechanical changes in a levitated system
Fluctuation theorems are fundamental extensions of the second law of
thermodynamics for small nonequilibrium systems. While work and heat are
equally important forms of energy exchange, fluctuation relations have not been
experimentally assessed for the generic situation of simultaneous mechanical
and thermal changes. Thermal driving is indeed generally slow and more
difficult to realize than mechanical driving. We here use feedback cooling
techniques to implement fast and controlled temperature variations of an
underdamped levitated microparticle that are one order of magnitude faster than
the equilibration time. Combining mechanical and thermal control, we verify the
validity of a fluctuation theorem that accounts for both contributions, well
beyond the range of linear response theory. Our system allows the investigation
of general far-from-equilibrium processes in microscopic systems that involve
fast mechanical and thermal changes at the same time
Prognostic Relevance of the Eighth Edition of TNM Classification for Resected Perihilar Cholangiocarcinoma
Objectives: In our study, we evaluated and compared the prognostic value and performance of the 6th, 7th, and 8th editions of the American Joint Committee on Cancer (AJCC) staging system in patients undergoing surgery for perihilar cholangiocarcinoma (PHC). Methods: Patients undergoing liver surgery with curative intention for PHC between 2002 and 2019 were identified from a prospective database. Histopathological parameters and stage of the PHC were assessed according to the 6th, 7th, and 8th editions of the tumor node metastasis (TNM) classification. The prognostic accuracy between staging systems was compared using the area under the receiver operating characteristic curve (AUC) model. Results: Data for a total of 95 patients undergoing liver resection for PHC were analyzed. The median overall survival time was 21 months (95% CI 8.1–33.9), and the three- and five-year survival rates were 46.1% and 36.2%, respectively. Staging according to the 8th edition vs. the 7th edition resulted in the reclassification of 25 patients (26.3%). The log-rank p-values for the 7th and 8th editions were highly statistically significant (p ≤ 0.01) compared to the 6th edition (p = 0.035). The AJCC 8th edition staging system showed a trend to better discrimination, with an AUC of 0.69 (95% CI: 0.52–0.84) compared to 0.61 (95% CI: 0.51–0.73) for the 7th edition. Multivariate survival analysis revealed male gender, age >65 years, positive resection margins, presence of distant metastases, poorly tumor differentiation, and lymph node involvement, such as no caudate lobe resection, as independent predictors of poor survival (p < 0.05). Conclusions: In the current study, the newly released 8th edition of AJCC staging system showed no significant benefit compared to the previous 7th edition in predicting the prognosis of patients undergoing liver resection for perihilar cholangiocarcinoma. Further research may help to improve the prognostic value of the AJCC staging system for PHC—for instance, by identifying new prognostic markers or staging criteria, which may improve that individual patient’s outcome
Literaturrundschau
Lteratur-Rundschau Elizabeth L. Eisenstein, Die Druckerpresse. Kulturrevolutionen im frühen modernen Europa (Michael Schmolke)Elmar Kos, Verständigung oder Vermittlung? Die kommunikative Ambivalenz als Zugangsweg einer theologischen Medienethik (Lars Rademacher)Ruth Ayaß, Das Wort zum Sonntag. Fallstudie einer kirchlichen Sendereihe (Susanne Kampmann)Steffen W. Rillebrecht (Hg.), Kirchliches Marketing (Susanne Kampmann)Joachim-Felix Leonhard (Hg.), Programmgeschichte des Hörfunks in der Weimarer Republik (Susanne Kampmann)Hans Magnus Enzensberger, Baukasten zu einer Theorie der Medien. Kritische Diskurse zur Pressefreiheit (Susanne Kampmann
Securing Wireless Communication in Critical Infrastructure: Challenges and Opportunities
Critical infrastructure constitutes the foundation of every society. While
traditionally solely relying on dedicated cable-based communication, this
infrastructure rapidly transforms to highly digitized and interconnected
systems which increasingly rely on wireless communication. Besides providing
tremendous benefits, especially affording the easy, cheap, and flexible
interconnection of a large number of assets spread over larger geographic
areas, wireless communication in critical infrastructure also raises unique
security challenges. Most importantly, the shift from dedicated private wired
networks to heterogeneous wireless communication over public and shared
networks requires significantly more involved security measures. In this paper,
we identify the most relevant challenges resulting from the use of wireless
communication in critical infrastructure and use those to identify a
comprehensive set of promising opportunities to preserve the high security
standards of critical infrastructure even when switching from wired to wireless
communication.Comment: Author's version of a paper accepted for publication in Proceedings
of the 20th EAI International Conference on Mobile and Ubiquitous Systems:
Computing, Networking and Services (MobiQuitous 2023
Impact of surface structure and feed gas composition on Bacillus subtilis endospore inactivation during direct plasma treatment
This study investigated the inactivation efficiency of cold atmospheric pressure plasma treatment on Bacillus subtilis endospores dependent on the used feed gas composition and on the surface, the endospores were attached on. Glass petri-dishes, glass beads, and peppercorns were inoculated with the same endospore density and treated with a radio frequency plasma jet. Generated reactive species were detected using optical emission spectroscopy. A quantitative polymerase chain reaction (qPCR) based ratio detection system was established to monitor the DNA damage during the plasma treatment. Argon + 0.135% vol. oxygen + 0.2% vol. nitrogen as feed gas emitted the highest amounts of UV-C photons and considerable amount of reactive oxygen and nitrogen species. Plasma generated with argon + 0.135% vol. oxygen was characterized by the highest emission of reactive oxygen species (ROS), whereas the UV-C emission was negligible. The use of pure argon showed a negligible emission of UV photons and atomic oxygen, however, the emission of vacuum (V)UV photons was assumed. Similar maximum inactivation results were achieved for the three feed gas compositions. The surface structure had a significant impact on the inactivation efficiency of the plasma treatment. The maximum inactivation achieved was between 2.4 and 2.8 log10 on glass petri-dishes and 3.9 to 4.6 log10 on glass beads. The treatment of peppercorns resulted in an inactivation lower than 1.0 log10. qPCR results showed a significant DNA damage for all gas compositions. Pure argon showed the highest results for the DNA damage ratio values, followed by argon + 0.135% vol. oxygen + 0.2% vol. nitrogen. In case of argon + 0.135% vol. oxygen the inactivation seems to be dominated by the action of ROS. These findings indicate the significant role of VUV and UV photons in the inactivation process of B. subtilis endospores
- …