1,721,263 research outputs found
IDENTIFICATION OF MAGNETIC FIELDS BY CHARGED PROJECTILES DATA
No full textThe problem of direct measurement of magnetic fields is in several cases not trivial when the region of interest is not directly accessible, or when conventional probes could be of disturbance. There are several “indirect” schemes, based on different physical effects, proposed as alternative to direct probing. We discuss here a novel technique for the identification of 1-D and 2-D magnetic fields, based on the analysis of trajectories of charged projectiles crossing the region under analysis. The magnetic field map is obtained through an inverse formulation of the motion problem of charged particles in the field. The inverse problem is solved by minimization procedures that identify the coefficients of suitable representations for the field. In this way we are able to identify typical magnetic field configurations, with great accuracy even in presence of noisy data. We give an overview on the method for the 1-D and 2-D cases, with reference to the field representation and the used optimization algorithms; moreover the robustness of the technique in presence of noisy data is assessed via a numerical analysis
IDENTIFICATION OF MAGNETIC FIELDS BY CHARGED PROJECTILES DATA
No full textThe problem of direct measurement of magnetic fields is in several cases not trivial when the region of interest is not directly accessible, or when conventional probes could be of disturbance. There are several “indirect” schemes, based on different physical effects, proposed as alternative to direct probing. We discuss here a novel technique for the identification of 1-D and 2-D magnetic fields, based on the analysis of trajectories of charged projectiles crossing the region under analysis. The magnetic field map is obtained through an inverse formulation of the motion problem of charged particles in the field. The inverse problem is solved by minimization procedures that identify the coefficients of suitable representations for the field. In this way we are able to identify typical magnetic field configurations, with great accuracy even in presence of noisy data. We give an overview on the method for the 1-D and 2-D cases, with reference to the field representation and the used optimization algorithms; moreover the robustness of the technique in presence of noisy data is assessed via a numerical analysis
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Fast Prototyping of a Solver for Reduct-based ELP Semantics
Full text linkSeveral semantic approaches have been proposed over time for Epistemic Logic Programs (ELPs), which is an extension to Answer Set Programming (ASP) with epistemic operators. ELP semantics has been defined, in various ways, in terms of world views, which are sets whose elements are sets of atoms. Several semantic approaches are Reduct-based, i.e., extend to ELPs what done for ASP, in the sense that in order to find the world views of a given program they propose to: start with a candidate world view; build the reduct of the program with respect to this candidate world view, according to some specific definition of such reduct; compute the set of stable models of the reduct; check whether the candidate world view is indeed a world view, which is the case if it coincides with the set of stable models of the reduct. Solvers have been developed for some of these approaches, but new semantics/variations have been introduced, and are likely to be introduced in the future, as there is no consensus yet on the “right” semantics. We propose a fast-prototyping approach to obtain a solver for any reduct-based semantics, with the advantage to be able to experiment the approach on small/medium programs, and not only on very small programs as done so far, prior to undertaking the costly process of developing a dedicated solver
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