322,968 research outputs found
Differential equations for real-structured defectivity measures.
No full textLet be a real matrix with all distinct eigenvalues. We propose a new method for the computation of the distance of the matrix from the set of real defective matrices, i.e., the set of those real matrices with at least one multiple eigenvalue with algebraic multiplicity larger than its geometric multiplicity.
For 0 < \eps \le w_\R(A), this problem is closely related to the computation of the most ill-conditioned \eps-pseudoeigenvalues of , that is points in the \eps-pseudospectrum of characterized by the highest condition number.
The method we propose couples a system of differential equations on a low rank manifold which determines the \eps-pseudoeigenvalue closest to coalesce, with a fast Newton-like iteration aiming to determine the minimal value \eps such that an \eps-pseudoeigenvalue becomes defective.
The method has a local behaviour; this means that in general we find upper bounds for . However, they usually provide good approximations, in those (simple) cases where we can check this.
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The methodology can be extended to a structured matrix, where it is required that the distance is computed within some manifold defining the structure of the matrix. In this paper we extensively examine the case of real matrices. As far as we know, there do not exist methods in the literature able to compute such distance
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Architecture and Decoration of the Propylon at Seuthopolis
No full textThe architectural and decorative dataset concerning Seuthopolis, the royal capital of the Odrysian Kingdom in the Tundzha Valley (today Bulgaria), remains notably limited, hindering a full appreciation of its original grandeur. This article addresses this gap by presenting newly (re)discovered findings related to the propylon of the royal palace (basileion) within the fortified citadel at the northeastern corner of the city. This represents the first attempt to reconstruct the architectural and decorative features of this significant structure based on material evidence. We also explore a potential connection between Seuthopolis and Samothrace, specifically the influence of the cult of the Great Gods, suggesting that decorative elements of Samothrace may have been replicated at Seuthopolis. In a broader context, this analysis of architectural marbles paves the way for a reassessment of the debated locations of both the royal palace and the temple of the Great Gods in the city. Our study also aims to shed light on the political dynamics between the Odrysian and Macedonian royal families, particularly in the aftermath of Macedonian expansion into Thrace during the 4th century BC. Ultimately, the findings contribute to a deeper understanding of the Macedonian role in the dissemination of North Aegean religious practices and architectural styles in the region
Clinical markers predictive of primary inefficacy: a "real life" retrospective study in psoriatic patients treated with etanercept.
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