635,631 research outputs found
Circular Bernstein polynomial distributions
No full textThis paper introduces a new non-parametric approach to the modeling of circular data, based on the use of Bernstein polynomial densities which generalizes the standard Bernstein polynomial model to account for the specific characteristics of circular data. It is shown that the trigonometric moments of the proposed circular Bernstein polynomial distribution can all be derived in closed form. We comment on how to fit the Bernstein polynomial density approximation to a sample of data and illustrate our approach with a real data example.Circular data, Non-parametric modeling, Bernstein polynomials
Asymptotic properties of the Bernstein density copula for dependent data
No full textCopulas are extensively used for dependence modeling. In many cases the data does not reveal how the dependence can be modeled using a particular parametric copula. Nonparametric copulas do not share this problem since they are entirely data based. This paper proposes nonparametric estimation of the density copula for α-mixing data using Bernstein polynomials. We study the asymptotic properties of the Bernstein density copula, i.e., we provide the exact asymptotic bias and variance, we establish the uniform strong consistency and the asymptotic normality.nonparametric estimation, copula, Bernstein polynomial, α-mixing, asymptotic properties, boundary bias
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
A semi-parametric model for circular data based on mixtures of beta distributions
No full textThis paper introduces a new, semi-parametric model for circular data, based on mixtures of
shifted, scaled, beta (SSB) densities. This model is more general than the Bernstein polynomial
density model which is well known to provide good approximations to any density with finite
support and it is shown that, as for the Bernstein polynomial model, the trigonometric moments of
the SSB mixture model can all be derived.
Two methods of fitting the SSB mixture model are considered. Firstly, a classical, maximum
likelihood approach for fitting mixtures of a given number of SSB components is introduced. The
Bayesian information criterion is then used for model selection. Secondly, a Bayesian approach
using Gibbs sampling is considered. In this case, the number of mixture components is selected
via an appropriate deviance information criterion.
Both approaches are illustrated with real data sets and the results are compared with those
obtained using Bernstein polynomials and mixtures of von Mises distributions
Variations on the Author
No full text“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
Educational technology - mapping the terrain with Bernstein as cartographer
No full textThis is the accepted version of the following article: Czerniewicz, L. 2010. Educational technology - mapping the terrain with Bernstein as cartographer. Journal of Computer Assisted Learning. 26(6): 523-534., which has been published in final form at: http://dx.doi.org/10.1111/j.1365-2729.2010.00359.x.This paper uses the literature of educational technology as the site of analysis in order to map the field of educational technology. Having considered Kuhn and Bourdieu's theories, the paper frames the analysis of the field in Bernsteinian terms as a horizontal knowledge structure in a vertical knowledge discourse. Using the concepts of interacting discursive planes, the paper maps the field in terms of its general approach planes and its problem planes. Finally, the paper shows that researchers in the field themselves acknowledge its weak grammar, and calls for commensurability of approaches to be acknowledged in order for robust knowledge to be developed and the legitimacy of the field to be enhanced
Micro-blogging adoption in the enterprise: an empirical analysis
No full textGiven the increasing interest in using social software for company-internal communication and collaboration, this paper examines drivers and inhibitors of micro-blogging adoption at the workplace. While nearly one in two companies is currently planning to introduce social software, there is no empirically validated research on employees’ adoption. In this paper, we build on previous focus group results and test our research model in an empirical study using Structural Equation Modeling. Based on our findings, we derive recommendations on how to foster adoption. We suggest that micro-blogging should be presented to employees as an efficient means of communication, personal brand building, and knowledge management. In order to particularly promote content contribution, privacy concerns should be eased by setting clear rules on who has access to postings and for how long they will be archived
Bernstein polynomial's applications
No full textBu çalışmada Bernstein polinomları tanımlanmış ve önceden verilmiş olan çeşitli özellikleri kullanılarak, Bernstein polinomları ile ilgili yeni sonuçlar bulunmuştur. Bu tez dört bölümden oluşmaktadır. Birinci bölümde çalışmanın diğer bölümlerine temel oluşturacak kavramlar ve teoremler verilmiştir. Ayrıca Gama ve Beta fonksiyonları tanımlanmış ve bu fonksiyonlarla ilgili temel özellikler verilmiştir. İkinci bölümde Bernstein polinomları tanımlanmış ve Bernstein polinomları ile ilgili temel özellikler verilmiştir. Üçüncü bölümde önce Bernstein polinomlarının belirli integralleri incelenmiş ve daha sonra Bernstein polinomlarının çarpımlarının belirli integrallerine yer verilmiştir. Ayrıca Bernstein polinomlarının Gama ve Beta fonksiyonlarıyla olan ilişkisi verilmiştir. Çalışmanın son bölümü olan dördüncü bölümde Bernstein polinomlarının türevleriyle ilgili temel bir sonuçtan yola çıkılarak, öncelikle Bernstein polinomlarının türevlerinin genellemesi verilmiştir. Daha sonra üçüncü bölümdeki Bernstein polinomlarının belirli integralleri ve Bernstein polinomlarının çarpımlarının belirli integrallerinden esinlenerek, Bernstein polinomlarının çarpımlarının türevleri ile ilgili yeni sonuçlar elde edilmiştir.In this work, Bernstein polynomials are defined and from using the several properties of Bernstein polynomials which are given before, some new results about Bernstein polynomias are found. The thesis consists of four chapters. In the first chapter, the preliminary notions which are to be used in later chapters are given. Besides, Gamma and Beta functions are defined and some basic properties of these functions are given. In the second chapter, Bernstein polynomials are defined and the basic properties about Bernstein polynomials are given. In the third chapter, firstly the integral of the Bernstein polynomials are investigated and then, the integral of the multiplication of the Bernstein polynomials are given. Besides, Bernstein polynomials relations with Gamma and Beta functions are given. In the fourth chapter which is the last one, from a basic property of the derivative of Bernstein polynomials, firstly generalization of the derivative of Bernstein polynomials are given. After that, some new results are inspired from the third chapter, which is about the multiplication of the derivation of Bernstein polynomials.TÜBİTA
Towards a Unified Theory of Sparsification for Matching Problems
No full textIn this paper, we present a construction of a "matching sparsifier", that is, a sparse subgraph of the given graph that preserves large matchings approximately and is robust to modifications of the graph. We use this matching sparsifier to obtain several new algorithmic results for the maximum matching problem:
- An almost (3/2)-approximation one-way communication protocol for the maximum matching problem, significantly simplifying the (3/2)-approximation protocol of Goel, Kapralov, and Khanna (SODA 2012) and extending it from bipartite graphs to general graphs.
- An almost (3/2)-approximation algorithm for the stochastic matching problem, improving upon and significantly simplifying the previous 1.999-approximation algorithm of Assadi, Khanna, and Li (EC 2017).
- An almost (3/2)-approximation algorithm for the fault-tolerant matching problem, which, to our knowledge, is the first non-trivial algorithm for this problem.
Our matching sparsifier is obtained by proving new properties of the edge-degree constrained subgraph (EDCS) of Bernstein and Stein (ICALP 2015; SODA 2016) - designed in the context of maintaining matchings in dynamic graphs - that identifies EDCS as an excellent choice for a matching sparsifier. This leads to surprisingly simple and non-technical proofs of the above results in a unified way. Along the way, we also provide a much simpler proof of the fact that an EDCS is guaranteed to contain a large matching, which may be of independent interest
Exponential Bernstein operators
No full textBu tez dört bölümden oluşmaktadır. Birinci bölümde tezin amacı ve kaynak özetleri hakkında bilgiler verilmiştir. İkinci bölümde tezde kullanılacak temel teoremler, tanımlar ve bazı eşitsizlikler verilmiştir. Üçüncü bölümde tezin temelini oluşturan üstel Bernstein operatörü ve bu operatörü oluşturan üstel Bernstein polinomları tanımlanmıştır. Bu operatörün yakınsaklık özellikleri ile ilgili teoremler verilmiş, lineer pozitif operatör olduğu gösterilmiş, düzgün yakınsaklığı, yaklaşım hızı ve asimptotik yaklaşımı incelenmiş ve şekil koruma özellikleri gösterilmiştir. Aynı zamanda üstel Bernstein polinomlarının indirgeme bağıntısı incelenmiş, bu polinomların simetrik olduğu, negatif olmadığı ve birim parçalanış olduğu gösterilmiştir. Dördüncü bölümde üstel Bernstein operatörünün hangi durumlarda daha iyi olduğunu gösteren fonksiyon ailesi bulunmuştur. Ayrıca üstel Bernstein operatörü ve klasik Bernstein operatörü arasında grafik ve nümerik tablolar yardımı ile karşılaştırmalar yapılmış, böylece üstel Bernstein operatörünün Klasik Bernstein operatöründen daha iyi yakınsadığı gösterilmiştir. Son bölümde ise üstel Bernstein Operatörünün yaklaşımı hakkında bilgi verilmiştir.The thesis consists of three chapters. The aim of the study is given in the first chapter. In the second chapter, some fundamental concepts, definitions and inequalities used throughout the thesis are given. In the third chapter, exponential Bernstein operator and exponential Bernstein polynomials forming this operator are defined. Theorems related to approximation properties of the operators are given. This operator has been shown to be a lineer positive operator. The smooth convergence, approach speed and asiptotic approach of this operator were investigated and this operator's shape preservation properties are shown. At the same time , the reduction relation of exponential Bernstein polynomials was examined, it was shown that polynomials of exponential Bernstein were symmetrical, not negative and unit fragmentation. In the fourth chapter, a family of functions were found which showed the better conditions of the exponential Bernstein operator. In addition, comparisons between graphical and numerical tables were made between the exponential Bernstein and the classical Bernstein operator. Thus, it has been shown that the operator of the exponential Bernstein has a better approximation than the classical Bernstein operator. At the end, information was given about the approach of the exponential Bernstein operator
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