So far and yet so near - accelerating distributed joins with CXL. - In: 20th International Workshop on Data Management on New Hardware (DaMoN 2024), (2024), 7, insges. 9 S.
Distributed partitioned joins are one of the most expensive operators in distributed DBMSs where a major part of the execution is attributed to network transfer costs. Although high-speed network technologies, such as RDMA, can lower this cost, they still come with significantly higher latency than local DRAM access. The emerging CXL interconnect protocol promises to provide direct and cache-coherent access to remote memory while offering byte-addressable memory access without CPU intervention. For short-distance communication in distributed DBMSs, CXL represents an interesting alternative for low-latency requirements. In this work, we explore how CXL can be leveraged for engine-internal communication and data exchange. We discuss and apply communication strategies to distributed joins. We emulate various CXL characteristics based on optimistic and pessimistic assumptions on the real performance of upcoming CXL devices and evaluate their impact on the execution of distributed joins. Our results show that CXL has the potential to improve distributed join performance.
https://doi.org/10.1145/3662010.3663449
Properties of AlCl3 guanidine deep eutectic solvent with addition of polyethylene oxide of different molecular weights supported by quantum-chemical calculation. - In: Journal of energy storage, ISSN 2352-152X, Bd. 96 (2024), 112665, S. 1-8
Deep eutectic solvent of AlCl3 with guanidine HCl was synthesized in the molar ratio 3:1 in the presence of polyethylene glycols of various molecular weights from 1500 to 5&hahog;106 g/mol. Concentration of polymer was 2.5 %, 5 % and 10 %. Temperature dependence between 25 and 70 ˚C of conductivity of each electrolyte was calculated from the cyclic voltammetry of aluminum deposition-stripping measurements. It was found that conductivity increases with molecular weight of polymer in the interval between 2 and 10 kD. This result was interpreted as binding of AlCl3 guanidine to two different sites which have hydroxyl (chain ends) and ether (middle chain) oxygen with relatively higher and lower binding energy respectively. Polymer with longer chain has more low energy binding sites which causes lesser binding and consequently higher conductivity of electrolyte. B3LYP-D3 and DLPNO-CCSD(T) computations support experimental results. DES are discussed in terms of Pearson HSAB principle.
https://doi.org/10.1016/j.est.2024.112665
C60 fullerene reduces the level of liver damage in chronic alcohol intoxication of rats. - In: Molecules, ISSN 1420-3049, Bd. 29 (2024), 13, 2951, S. 1-15
The liver is the main organ responsible for the metabolism of ethanol, which suffers significantly as a result of tissue damage due to oxidative stress. It is known that C60 fullerenes are able to efficiently capture and inactivate reactive oxygen species in in vivo and in vitro systems. Therefore, the purpose of this study is to determine whether water-soluble C60 fullerene reduces the level of pathological process development in the liver of rats induced by chronic alcohol intoxication for 3, 6, and 9 months, depending on the daily dose (oral administration; 0.5, 1, and 2 mg/kg) of C60 fullerene throughout the experiment. In this context, the morphology of the C60 fullerene nanoparticles in aqueous solution was studied using atomic force microscopy. Such biochemical parameters of experimental animal blood as ALT (alanine aminotransferase), AST (aspartate aminotransferase), GGT (gamma-glutamyl transferase) and ALP (alkaline phosphatase) enzyme activities, CDT (carbohydrate-deficient transferrin) level, values of pro-antioxidant balance indicators (concentrations of H2O2 (hydrogen peroxide) and GSH (reduced glutathione), activities of CAT (catalase), SOD (superoxide dismutase) and GPx (selenium-dependent glutathione peroxidase)), and pathohistological and morphometric features of liver damage were analyzed. The most significant positive change in the studied biochemical parameters (up to 29 ± 2% relative to the control), as markers of liver damage, was recorded at the combined administration of alcohol (40% ethanol in drinking water) and water-soluble C60 fullerenes in the optimal dose of 1 mg/kg, which was confirmed by small histopathological changes in the liver of rats. The obtained results prove the prospective use of C60 fullerenes as powerful antioxidants for the mitigation of pathological conditions of the liver arising under prolonged alcohol intoxication.
https://doi.org/10.3390/molecules29132951
Generative convective parametrization of a dry atmospheric boundary layer. - In: Journal of advances in modeling earth systems, ISSN 1942-2466, Bd. 16 (2024), 6, e2023MS004012, S. 1-20
Turbulence parametrizations will remain a necessary building block in kilometer-scale Earth system models. In convective boundary layers, where the mean vertical gradients of conserved properties such as potential temperature and moisture are approximately zero, the standard ansatz which relates turbulent fluxes to mean vertical gradients via an eddy diffusivity has to be extended by mass-flux parametrizations for the typically asymmetric up- and downdrafts in the atmospheric boundary layer. We present a parametrization for a dry and transiently growing convective boundary layer based on a generative adversarial network. The training and test data are obtained from three-dimensional high-resolution direct numerical simulations. The model incorporates the physics of self-similar layer growth following from the classical mixed layer theory of Deardorff by a renormalization. This enhances the training data base of the generative machine learning algorithm and thus significantly improves the predicted statistics of the synthetically generated turbulence fields at different heights inside the boundary layer, above the surface layer. Differently to stochastic parametrizations, our model is able to predict the highly non-Gaussian and transient statistics of buoyancy fluctuations, vertical velocity, and buoyancy flux at different heights thus also capturing the fastest thermals penetrating into the stabilized top region. The results of our generative algorithm agree with standard two-equation mass-flux schemes. The present parametrization provides additionally the granule-type horizontal organization of the turbulent convection which cannot be obtained in any of the other model closures. Our proof of concept-study also paves the way to efficient data-driven convective parametrizations in other natural flows.
https://doi.org/10.1029/2023MS004012
Port-Hamiltonian descriptor systems are relative generically controllable and stabilizable. - In: Mathematics of control, signals, and systems, ISSN 1435-568X, Bd. 0 (2024), 0, insges. 37 S.
The present work is a successor of Ilchmann and Kirchhoff (Math Control Signals Syst 33:359-377, 2021) on generic controllability and of Ilchmann and Kirchhoff (Math Control Signals Syst 35:45-76, 2022) on relative generic controllability of linear differential-algebraic equations. We extend the result from general, unstructured differential-algebraic equations to differential-algebraic equations of port-Hamiltonian type. We derive results on relative genericity. These findings are the basis for characterizing relative generic controllability of port-Hamiltonian systems in terms of dimensions. A similar result is proved for relative generic stabilizability.
https://doi.org/10.1007/s00498-024-00392-7
Minimizing the homogeneous L2-gain of homogeneous differentiators. - In: European journal of control, ISSN 1435-5671, Bd. 0 (2024), 0, 101039, S. 1-8
The differentiation of noisy signals using the family of homogeneous differentiators is considered. It includes the high-gain (linear) as well as robust exact (discontinuous) differentiator. To characterize the effect of noise and disturbance on the differentiation estimation error, the generalized, homogeneous L2-gain is utilized. Analog to the classical Lp-gain, it is not defined for the discontinuous case w.r.t. disturbances acting on the last channel. Thus, only continuous differentiators are addressed. The gain is estimated using a differential dissipation inequality, where a scaled Lyapunov function acts as storage function for the homogeneous L2 supply rate. The fixed differentiator gains are scaled with a gain-scaling parameter similar to the high-gain differentiator. This paper shows the existence of an optimal scaling which minimizes the homogeneous L2-gain estimate and provides a procedure to obtain it locally. Differentiators of dimension two are considered and the results are illustrated via numerical evaluation and a simulation example.
https://doi.org/10.1016/j.ejcon.2024.101039
Digitalization attempts in higher education: the role of imprinting and the effect of business departments. - In: Studies in higher education, ISSN 1470-174X, Bd. 0 (2024), 0, S. 1-19
In recent decades, higher education institutions (HEIs) have increasingly been exposed to a market logic that has led them to adopt structures and practices that are common in for-profit firms. In our study, we analyze how HEIs react to the increasing demands of digitalization and which factors explain the adoption of relevant structures. Based on 379 HEIs in Germany, our findings show that imprinting is of great importance for the implementation of a position for digitalization - that is, HEIs founded in a more recent phase of higher education in Germany are more likely to create a leadership position for digitalization. At the same time, we find that imprinting has no effect on the creation of more operational positions for digitalization but that the existence of a business department in HEIs has a positive effect. We discuss these findings in the context of higher education research and questions about factors influencing the adoption of practices and structures in HEIs.
https://doi.org/10.1080/03075079.2024.2355349
Consequences of the potential gauging process for modeling electromagnetic wave propagation. - In: IEEE open journal of antennas and propagation, ISSN 2637-6431, Bd. 0 (2024), 0, S. 1-12
This predominantly theoretical article focuses on a qualitative discussion of peculiarities, which are introduced in practical electromagnetic (EM) wave propagation scenarios when the gauge for the electrodynamic potentials is not chosen in accordance to the appropriate space-time metric of the underlying physical framework. Based on ordinary vector calculus, this is done for the viewpoint of radio frequency (RF) engineers by using two examples of guided EM waves: one large-scale case of a terrestrial scenario and one small-scale case involving a device level setup. Readers may benefit especially from this practical orientation, since gauging is often analyzed primarily mathematical by solely arguing on terms of equations instead of discussing concrete applications. The provided context aims to enhance the usual perspective and is applicable for a wide class of situations involving various wave types at any frequency.
https://doi.org/10.1109/OJAP.2024.3412162
Investigation of Tl-doped silicon by low-temperature photoluminescence during light-induced degradation treatments. - In: Physica status solidi, ISSN 1862-6319, Bd. n/a (2024), n/a, 2400287, S. 1-6
Scientific progress is made in understanding photoluminescence (PL) lines in thallium-doped silicon. Two PL lines called A and P, which appear after quenching, are found to exhibit irreversible as well as reversible behavior under the application of light-induced degradation (LID) treatments. The reversible behavior is similar to changes of a P line in indium-doped silicon due to LID treatments, which have led to the identification of this P line to be caused by an InSi-Sii-defect. By exploiting the metastability of defects from the ASi-Sii category, the experimental findings of this study indicate that the underlying defect for the A and P line in thallium-doped silicon is the TlSi-Sii-defect.
https://doi.org/10.1002/pssa.202400287
Analysis of deformation in tensegrity structures with curved compressed members. - In: Meccanica, ISSN 1572-9648, Bd. 0 (2024), 0, insges. 12 S.
Tensegrity structures are prestressed structures consisting of compressed members connected by prestressed tensioned members. Due to their properties, such as flexibility and lightness, mobile robots based on these structures are an attractive subject of research and are suitable for space applications. In this work, a mobile robot based on a tensegrity structure with two curved members connected by eight tensioned strings is analyzed in terms of deformation in the curved members. Further, the difference in locomotion trajectory between the undeformed and deformed structure after the prestress is analyzed. For that, the theory of large deflections of rod-like structures is used. To determine the relationship between acting forces and the deformation, the structure is optimized using minimization algorithms in Python. The results are validated by parameter studies in FEM. The analysis shows that the distance between the two curved members significantly influences the structure’s locomotion. It can be said that the deformation of the components significantly influences the locomotion of tensegrity structures and should be considered when analyzing highly compliant structures.
https://doi.org/10.1007/s11012-024-01833-y