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Converse bounds on modulation-Estimation performance for the Gaussian multiple-access channel
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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
On Jacob Ziv's Individual-Sequence Approach to Information Theory
Get PDFThis article stands as a tribute to the enduring legacy of Jacob Ziv and his
landmark contributions to information theory. Specifically, it delves into the
groundbreaking individual-sequence approach -- a cornerstone of Ziv's academic
pursuits. Together with Abraham Lempel, Ziv pioneered the renowned Lempel-Ziv
(LZ) algorithm, a beacon of innovation in various versions. Beyond its original
domain of universal data compression, this article underscores the broad
utility of the individual-sequence approach and the LZ algorithm across a wide
spectrum of problem areas. As we traverse through the forthcoming pages, it
will also become evident how Ziv's visionary approach has left an indelible
mark on my own research journey, as well as on those of numerous colleagues and
former students. We shall explore, not only the technical power of the LZ
algorithm, but also its profound impact on shaping the landscape of information
theory and its applications.Comment: 10 pages, 3 figures, submitted to the IEEE BITS Magazine - The
Information Theory Magazin
Two New Families of Local Asymptotically Minimax Lower Bounds in Parameter Estimation
Get PDFWe propose two families of asymptotically local minimax lower bounds on parameter estimation performance. The first family of bounds applies to any convex, symmetric loss function that depends solely on the difference between the estimate and the true underlying parameter value (i.e., the estimation error), whereas the second is more specifically oriented to the moments of the estimation error. The proposed bounds are relatively easy to calculate numerically (in the sense that their optimization is over relatively few auxiliary parameters), yet they turn out to be tighter (sometimes significantly so) than previously reported bounds that are associated with similar calculation efforts, across a variety of application examples. In addition to their relative simplicity, they also have the following advantages: (i) Essentially no regularity conditions are required regarding the parametric family of distributions; (ii) The bounds are local (in a sense to be specified); (iii) The bounds provide the correct order of decay as functions of the number of observations, at least in all examples examined; (iv) At least the first family of bounds extends straightforwardly to vector parameters.26 pages, submitted for publicatio
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
Universal Slepian-Wolf coding for individual sequences
Get PDFWe establish a coding theorem and a matching converse theorem for separate
encodings and joint decoding of individual sequences using finite-state
machines. The achievable rate region is characterized in terms of the
Lempel-Ziv (LZ) complexities, the conditional LZ complexities and the joint LZ
complexity of the two source sequences. An important feature that is needed to
this end, which may be interesting on its own right, is a certain asymptotic
form of a chain rule for LZ complexities, which we establish in this work. The
main emphasis in the achievability scheme is on the universal decoder and its
properties. We then show that the achievable rate region is universally
attainable by a modified version of Draper's universal incremental Slepian-Wolf
(SW) coding scheme, provided that there exists a low-rate reliable feedback
link.Comment: 26 pages; submitted for publicatio
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