1,720,961 research outputs found
Алгоритми за изследване на комбинаторни обекти
Get PDFВТУ "Св. Св. Кирил и Методий", педагогически факултет, катедра "Алгебра и геометрия", 2003 г., присъждане на образователна и научна степен "доктор" на Валентин Пенев Бакоев, научна специалност 01.01.12 информатика. [Bakoev Valentin Penev; Бакоев Валентин Пенев
Distribution of The Boolean Functions of n Variables According to Their Algebraic Degrees
Get PDFKnowledge on the enumeration and distribution of
Boolean functions according to their algebraic degrees is
important for the theory as well as for its applications. As of now,
this knowledge is not complete; for example, it is well-known that
half of all Boolean functions have a maximal algebraic degree. In
this paper, a formula for the number of all Boolean functions of n
variables and algebraic degree = k is derived. A direct
consequence from it is the assertion (formulated already by
Claude Carlet) that when n →∞, almost half of all Boolean functions
of n variables have an algebraic degree = n−1. The results
obtained by this formula were used in creating the sequence
A319511 in the OEIS. The discrete probability of a random Boolean
function having a certain algebraic degree is defined and the
corresponding distribution is computed, for 3 ≤ n ≤ 10. Four
applications are considered: at the design and analysis of efficient
algorithms for exact or probabilistic computing the algebraic
degree of Boolean functions; when checking 4 test files for
representativeness; when creating benchmark files of Boolean functions
Fast Bitwise Implementation of the Algebraic Normal Form Transform
Get PDFThe representation of Boolean functions by their algebraic normal
forms (ANFs) is very important for cryptography, coding theory and
other scientific areas. The ANFs are used in computing the algebraic degree
of S-boxes, some other cryptographic criteria and parameters of errorcorrecting
codes. Their applications require these criteria and parameters to
be computed by fast algorithms. Hence the corresponding ANFs should also
be obtained by fast algorithms. Here we continue our previous work on fast
computing of the ANFs of Boolean functions. We present and investigate
the full version of bitwise implementation of the ANF transform.
The experimental results show that this implementation is
more than 25 times faster in comparison to the well-known byte-wise ANF
transform.
ACM Computing Classification System (1998): F.2.1, F.2.2
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Algorithmic approach to counting of certain types m-ary partitions
No full textAbstractPartitions of integers of the type mn as a sum of powers of m (the so-called m-ary partitions) and their counting is considered in this paper. Two algorithms for counting of m-ary partitions of sums, where each addend is mn, are developed. On the base of these algorithms some arithmetical and combinatorial properties, and also polynomial form representations of the number of such partitions are derived. An algorithm with a polynomial running time, which produces the coefficients of this polynomial and next computes the number of considered partitions, is proposed. Two applications, concerning counting problems of special types of m-ary trees and partitions of the Boolean cube, are given
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