1,720,997 research outputs found
A New Estimator for Stationary Distribution of the Inventory Model of Type (s, S)
No full text[Gokpinar, Esra; Gamgam, Hamza; Gokpinar, Fikri] Gazi Univ, Fac Sci, Dept Stat, Ankara, Turkey; [Khaniyev, Tahir] TOBB Univ Econ ; Technol, Dept Ind Engn, Ankara, TurkeyWe consider inventory model of type (s, S) which is used mostly in stock control policy. It is very important to know characteristics of an inventory model of type (s, S), such as stationary distribution. Using the straight line approach of Frees [1], we establish estimator for ergodic distribution of inventory model of type (s, S) and investigate asymptotic properties of this estimator such as consistency, asymptotic unbiasedness and asymptotic normality
Asymptotic Properties of the Straight Line Estimator for a Renewal Function
No full textIn estimation problems in renewal function, when the distribution is not known, nonparametric estimators of renewal function are used. Frees (1986a, Warranty analysis and renewal function estimation, Naval Res. Logist. Quart, 33, 361-372) proposed the nonparametric estimator of renewal function for large values of t. Frees's estimator is easy to apply in practice. It is a preferred estimator for large values of t. However, its statistical properties still have not been investigated in detailed. For this reason, in this study, we investigate asymptotic properties of this estimator such as consistency, asymptotic unbiasedness and asymptotic normality. Also Monte Carlo simulation study is given to assess the performance of this estimator according to value of renewal function. Simulation results indicate that in the large values of t, Frees estimator is sufficiently close to the renewal function for the Gamma distribution with various parameters.[Gokpinar, Esra; Gamgam, Hamza] Gazi Univ, Dept Stat, TR-06500 Ankara, Turkey; [Khaniyev, Tahir] TOBB Univ Econ ; Technol, Dept Ind Engn, TR-06500 Ankara, Turkey; [Khaniyev, Tahir] Natl Acad Sci, Inst Cybernet Azerbaijan, AZ-1141 Baku, Azerbaija
Estimators of the Moments for the Inventory Model of Type (s, S)
No full textThe inventory model of type (s, S) is one of the most common used inventory models used in many problems of stock control. It is very important to know statistical characteristics such as the moments of the inventory model of type (s, S). However, since the moments of the inventory model of type (s, S) depend on the moments of demands, they cannot be obtained easily in most of the time. For this reason, we focus on the estimation problem of the moments of the inventory model of type (s, S). In this study, we obtain the estimators of the moments of this process initially. Afterwards, the asymptotic statistical properties of these estimators such as consistency, asymptotic unbiasedness and asymptotic normality are investigated. We also give a detailed numerical example of these estimators of the moments of the inventory model of type (s, S).[Gokpinar, Esra; Gamgam, Hamza; Gokpinar, Fikri] Gazi Univ, Dept Stat, TR-06500 Ankara, Turkey; [Khaniyev, Tahir] TOBB Univ Econ ; Technol, Dept Ind Engn, TR-06500 Ankara, Turkey; [Khaniyev, Tahir] Natl Acad Sci Azerbaijan, Inst Cybernet, AZ-1141 Baku, Azerbaija
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
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