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Analysis of Topological Privacy Notions
Get PDFThe current state-of-the-art notions in statistical disclosure control face some problems in
real-world data privacy scenarios, by either making best-case assumptions or potentially
degrading the utility of the data. However, in 2017 Erdmann introduces two new syntactic
privacy notions for Relations: Attribute Privacy and Association Privacy. These notions
are defined over the topology of the released data. Notably, they do not include best-
case assumptions, and typically syntactic notions provide good data utility. It is thus
worthwhile to analyze their benefits and drawbacks in the context of existing notions.
Nevertheless, up to this point, no formal analysis has been performed, and no mechanism
has been given for these notions.
Therefore, in this work, we formally analyze the topological notions, providing theoretical
proofs about their protections, and compare them to the current state-of-the-art privacy
notions in statistical disclosure control. Further, we provide a mechanism to achieve
Attribute Privacy, whose utility we empirically analyze. Overall, we reveal multiple flaws
inherent to the topological notions, and come to the conclusion that they are not suited
as a generalized replacement for the existing relational data state-of-the-art. Additionally,
as Association Privacy has the protection goal of hiding associations between people,
we provide an analysis of Association Privacy in the context of graph data privacy. We
find that the existing syntactic graph privacy notion of k-security provides stronger
protections
Workflow-driven catalytic modulation from single-atom catalysts to Au–alloy clusters on graphene
Get PDFScattering of the three-dimensional cubic nonlinear Schrödinger equation with partial harmonic potentials
Get PDFSimulation-Based Investigation on Thermal Propagation in Li-ion Battery Modules with Regard to the Thermal Management System
Get PDFThermal propagation in Li-ion battery systems is affected by a wide range of influencing factors including chemical cell properties as well as thermal transport phenomena. Due to the dependence on thermal surroundings it is crucial to regard the entire battery system including peripheral components when assessing thermal runaway and propagation risks. This study proposes a simulation-based approach to support design and dimensioning of potential safety measures. It is based on a chemical model for the thermal runaway decomposition reactions combined with 3D thermal simulations. This is applied on exemplary ten cell battery pack in order to investigate on effects on heat transfer during thermal propagation. Insulation and cooling systems are included in the simulation environment for that purpose. It is found that propagation behavior significantly depends on their positioning within in pack and on thermal boundary conditions. Placing too many barriers may exacerbate hazardous situations instead of mitigating them due to heat accumulation effects. Cooling systems are shown to be able to support thermal runaway mitigation strategies but
their effectiveness is limited by thermal transport inside the battery cells
Model-independent search for T violation with T2HK and DUNE
Get PDFWe consider the time reversal (T) transformation in neutrino oscillations in a model-independent way by comparing the observed transition probabilities at two different baselines at the same neutrino energy. We show that, under modest model assumptions, if the transition probability around GeV measured at DUNE is smaller than the one at T2HK the T symmetry has to be violated. Experimental requirements needed to achieve good sensitivity to this test for T violation are to obtain enough statistics at DUNE for GeV (around the 2nd oscillation maximum), good energy resolution (better than 10%), and near-detector measurements with a precision of order 1% or better
The Pierre Auger Observatory Open Data
Get PDFThe Pierre Auger Collaboration has embraced the concept of open access to their research data since its foundation, with the aim of giving access to the widest possible community. A gradual process of release began as early as 2007 when 1% of the cosmic-ray data was made public, along with 100% of the space-weather information. In February 2021, a portal was released containing 10% of cosmic-ray data collected from 2004 to 2018, during Phase I of the Observatory. The Portal included detailed documentation about the detection and reconstruction procedures, analysis codes that can be easily used and modified and, additionally, visualization tools. Since then the Portal has been updated and extended. In 2023, a catalog of the 100 highest-energy cosmic-ray events examined in depth has been included. A specific section dedicated to educational use has been developed with the expectation that these data will be explored by a wide and diverse community including professional and citizen-scientists, and used for educational and outreach initiatives. This paper describes the context, the spirit and the technical implementation of the release of data by the largest cosmic-ray detector ever built, and anticipates its future developments
A Contribution to Friction in Timber Connections
Get PDFThe load-carrying capacity of connections with inclined screws can be increased due to friction in the shear plane. Surface modifications to increase the friction were investigated. Friction tests showed increased friction coefficients. Tests with connections showed increased load and stiffness values. An analytical model predicts the load well. This work provides insights into the short-term and long-term behaviour of connections with inclined screws and increased friction in the shear plane
Phase Transformation Processes in Coprecipitated Cu/Zn/Zr Methanol Catalyst Precursors—Insights into Suspension Aging Form Ultrafast Nucleation
Get PDFCatalyst precursors for methanol synthesis prepared by coprecipitation, such as Cu/Zn-based hydroxycarbonates, are generally formed within two steps. The initial precipitation phase (nucleation) leads to a suspension from which, in a subsequent aging phase, the final solid precursor is formed, thus providing the structural and morphological features required for later use in catalysis. Combing ultrafast continuous nucleation with sampling from batch-wise aging opens up the possibility to follow the evolution and transitions of solid phases during suspension aging. The temporal progression of the existence of the different phases in a Cu/ZnO/ZrO-based system is investigated by scanning electron microscopy, X-ray diffraction, and inductive coupled plasma optical emission spectroscopy . According to the findings of this study, the intermediate recrystallization reveals to be a yet unknown two-step process. The presence of an amorphous transient zinc depot of NaZn(CO) × 3 HO greatly influences the formation of the relevant zincian malachite catalyst precursor [(Cu,Zn)(OHCO], which is partly in contrast to reports on Cu/ZnO/AlO systems. Finally, a general mechanism including the relevant transformations during suspension aging in Cu/ZnO/ZrO systems is proposed, relying on a general thermodynamic approach, explaining the transient and final species
