1,720,984 research outputs found
Exploiting regularities for boolean function synthesis
No full textThe "regularity" of a Boolean function can be exploited for decreasing its minimization time. It has already been shown that the notion of autosymmetry is a valid measure of regularity, however such a notion has been studied thus far either in the theoretical framework of self-dual Boolean functions, or for the synthesis of a particular family of three-level logic networks. In this paper we show that the degree of autosymmetry of an arbitrary function can be computed implicitly in a very efficient way, and autosymmetry can then be exploited in any logic minimization context. Our algorithms make crucial use of Binary Decision Diagrams. A set of experimental results on the synthesis of standard benchmark functions substantiates the practical relevance of our theoretical results
Synthesis of integer multipliers in sum of pseudoproducts form
No full textWe discuss the realization of two standard multiplier structures in a three-level form based on EXOR, called sum of pseudoproducts (SPP for short). SPP extends the classical two-level sum of products form (SOP). Our study focuses on the minimization of the number of gates and levels of the circuits needed to construct Wallace-type multipliers, and a 54 × 54-bit multiplier. The basic building blocks explicitly studied are the 4 × 4 parallel multiply module, and the family of carry-save adders Ci, with i input lines, that compose the Wallace trees. We show that the ratio of the number of gates of Ci in SPP over SOP decreases exponentially with i, being very small even for small values of i (ratio > 0.2 for i = 9). The evaluation of power, speed, and chip area with three different standard tools also shows the interest of the proposed approach
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 Three-Level Logic Minimization Based on Autosymmetry
No full textIn the framework of SPP minimization, a three level logic
synthesis technique developed in recent years, we exploit the
``regularity'' of Boolean functions to decrease minimization time.
Our main results are: 1) the regularity of a Boolean function
of variables is expressed by its \emph{autosymmetry
degree} (with ), where means no
regularity (that is, we are not able to provide any advantage
over standard synthesis); 2) for the function is {\em
autosymmetric}, and a new function is identified in
polynomial time; is ``equivalent'' to, but smaller than ,
and depends on variables only; 3) given a minimal SPP form
for , a minimal SPP form for is built in linear time;
4) experimental results show that 61\% of the functions in the
classical \textsc{Espresso} benchmark suite are autosymmetric,
and the SPP minimization time for them is critically reduced; we
can also solve cases otherwise practically intractable. We
finally discuss the role and meaning of autosymmetry
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
