1,720,958 research outputs found
De-embedding procedure based on computed/measured data set for PCB structures characterization
No full textThis paper uses a de-embedding procedure, based on measured and numerically computed S-parameters, to obtain the characterization of portions of a structure difficult to obtain by direct measurements. The results are validated by measurements and independent calculations
S-parameters characterization of through, blind, and buried via holes
No full textA method for de-embedding the scattering parameters matrix for single-end or differential through, buried, and blind via holes in multilayer printed circuit board for high-speed digital applications is presented. The proposed technique starts from a measurement or simulation of the structure containing the discontinuity and, after the structure's partitioning, extracts the scattering parameters of the required discontinuity. The procedure is applied to different kinds of single-ended and differential via holes and is validated by measurements. The Finite Integration Technique is used to perform the needed three-dimensional electromagnetic simulations. Due to its reduced CPU time, the proposed methodology is suitable for a parametric analysis on the electrical performance of the via holes discontinuities and it gives useful results for the extraction of accurate computer-aided design models
Grounding, unbalancing and length effects on termination voltages of a twinax cable during bulk current injection
No full textBy means of an equivalent SPICE circuit of a two-parallel-wires shielded cable (twinax), the effects on the induced voltages at the cable's terminations during a bulk current injection are studied for different shield's grounding, different cable's asymmetries or unbalancing and different lengths of the cable. The analysis is carried out both in frequency and time domain
Scalable compact models for fast design optimization of complex electromagnetic systems
No full textWe propose a new parametric macromodeling technique for complex electromagnetic (EM) systems described by scattering parameters, which are parameterized by multiple design variables such as layout or substrate feature. The proposed technique is based on an efficient and reliable combination of rational identification, a procedure to find scaling and frequency shifting system coefficients, and positive interpolation schemes. Parametric macromodels can be used for efficient and accurate design space exploration and optimization. A design optimization example for a complex EM system is used to validate the proposed parametric macromodeling technique in a practical design process flow. (c) 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012
Efficient design optimization of complex electromagnetic systems using parametric macromodeling techniques
No full textWe propose a new parametric macromodeling technique for complex electromagnetic systems described by scattering parameters, which are parameterized by multiple design variables such as layout or substrate feature. The proposed technique is based on an efficient and reliable combination of rational identification, a procedure to find scaling and frequency shifting system coefficients, and positive interpolation schemes. Parametric macromodels can be used for efficient and accurate design space exploration and optimization. A design optimization example for a complex electromagnetic system is used to validate the proposed parametric macromodeling technique in a practical design process flow
Extraction of a SPICE via model from full-wave modeling for differential signaling
No full textThe paper presents a procedure for building SPICE models for via transitions in differential signaling. The method of extracting parameters of SPICE models from a full-wave simulation tool is demonstrated. Then the validity of the SPICE models is studied by comparing the solution from the SPICE models with that from the full-wave simulation
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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