Improving Magnet Aperture by Estimation of Errors due to the Influence of Temperature Gradients during Magnet Axis Measurements

The LHC magnet axes are measured from both ends of the magnet. These two redundant measurements are combined to get a reliable measurement result and to compensate calibration errors. When the two measurements are put together, we observe a "saw tooth" effect due to the fact that the two measurements are, in general, not identical. It can be seen that this effect is larger than expected from the accuracy of the measurements which motivated the study. Effects of temperature gradients in the cold bore tube of the magnet during measurements have been observed [6] and we show that this effect is the most probable explanation for our observations of the geometry measurements in the vertical plane. The aim of this work is to present an algorithmic approach to filter this effect and improve the measurement results. The effect is relatively small but for some magnets the displacement is up to -0.3 mm. The magnet positioning is controlled to 0.1 mm. Our analysis shows that by applying this correction we can insure the best positioning of the magnets (including the spool pieces) in the tunnel in the vertical plane

On the Optimality of CVOD-based Column Selection

While there exists a rich array of matrix column subset selection problem (CSSP) algorithms for use with interpolative and CUR-type decompositions, their use can often become prohibitive as the size of the input matrix increases. In an effort to address these issues, the authors in \cite{emelianenko2024adaptive} developed a general framework that pairs a column-partitioning routine with a column-selection algorithm. Two of the four algorithms presented in that work paired the Centroidal Voronoi Orthogonal Decomposition (\textsf{CVOD}) and an adaptive variant (\textsf{adaptCVOD}) with the Discrete Empirical Interpolation Method (\textsf{DEIM}) \cite{sorensen2016deim}. In this work, we extend this framework and pair the \textsf{CVOD}-type algorithms with any CSSP algorithm that returns linearly independent columns. Our results include detailed error bounds for the solutions provided by these paired algorithms, as well as expressions that explicitly characterize how the quality of the selected column partition affects the resulting CSSP solution.Comment: 15 pages. Typos have been corrected, references added, and language update

The Ubuntu Principle in the Internal and Foreign Policy of South Africa

This article discusses the peculiar features of South Africa’s foreign policy, which became the fifth member of BRICS in 2011. The decision for South Africa’s accession to BRICS was based on the principles of the country's foreign policy; facilitating the establishment of a multipolar, just, and equitable world order, striving for the development and prosperity of Africa. The focus is on the notion of Ubuntu and the formation of foreign policy in South Africa since the 90s of the 20th century. Ubuntu is one of the basic philosophical concepts and organizational principles of the Bantu-speaking people of Africa. After the fall of the apartheid regime in South Africa and the democratic transformation undertaken in 1994, the philosophy of Ubuntu was adopted by the leaders of the country and became an instrument regulating public life, became a regular fixture of domestic public policy as well as firmly entrenching itself as one of the key principles of foreign policy. The purpose of this paper is to determine when the philosophy of Ubuntu became part of the political landscape of South Africa, to establish the degree of this concept’s influence on the external and internal political rhetoric, and to determine the tools for the dissemination of Ubuntu by the government of South Africa. The scientific novelty consists in a comprehensive analysis of state documents and their study with reference to content on the Ubuntu concept. Earlier, such an analysis has not been introduced into the scientific study of our country. The conclusions reached by the author assert a high degree of integration of the concept of Ubuntu in the strategic course of the South Africa's policy

Optimization of Neutrino Rates from the EURISOL Beta-Beam Accelerator Complex

The beta beam concept for the production of intense (anti-)neutrino beams is now well established. A baseline design has recently been published for a beta-beam facility at CERN. It has the virtue of respecting the known limitations of the CERN PS and SPS synchrotrons, but falls short of delivering the requested annual rate of neutrinos. We report on a first analysis to increase the rate using the baseline ions of 6He and 18 Ne. A powerful method to understand the functional dependence of the many parameters that influence the figure of merit for a given facility is available with modern analytical calculation software. The method requires that a symbolic analytical description is produced of the full accelerator chain. Such a description has been made using Mathematica for the proposed beta beam facility at CERN. The direct access from Mathematica to an ORACLE database for reading basic design parameters and re-injecting derived parameters for completion of the parameter list is both convenient and efficient