1,720,958 research outputs found
Online packing of rectangles and d-dimensional cubes
No full textWydział Matematyki i InformatykiPrzedmiotem tej rozprawy jest pakowanie online d-wymiarowych boxów oraz d-wymiarowych kostek. Oznaczmy przez b(d) [przez c(d), odpowiednio] największą liczbę taką, że dowolny ciąg d-wymiarowych boxów [kostek, odpowiednio] o krawędziach długości co najwyżej 1 i całkowitej objętości nie większej niż b(d) [niż c(d), odpowiednio] można upakować w d-wymiarowej kostce jednostkowej (tzn. kostce o krawędziach długości 1). W rozdziale 2 prezentuję algorytm pakowania online prostokątów. Stosując ten algorytm pokazuję, że b(2) jest większe lub równe 0,2837. Ponadto w rozdziale 3 dowodzę, że b(d) jest nie mniejsze niż (3-2√2)·3-d dla d większego niż 2. W rozdziale 4 wykazuję, że jeżeli n jest nie mniejsze niż 3 oraz d jest równe 3 lub 4 albo jeżeli n jest liczbą naturalną dodatnią oraz d większe niż 4, to dowolny ciąg d-wymiarowych kostek o krawędziach długości nie większej niż 1 i o całkowitej objętości co najwyżej (n+1) ·2-d można upakować online w n jednostkowych d-wymiarowych kostkach. W rozdziale 5 pokazuję, że powyższy wynik jest słuszny również dla n = 1 i d = 4, to znaczy, że c(4) jest większe lub równe 1/8. Jest to najważniejsza część niniejszej rozprawy. W rozdziale 6 podaję wyniki (bez dowodów) dotyczące zagadnienia pakowania do binów.In this dissertation I examine the online packing of d-dimensional boxes and d-dimensional cubes. Denote by b(d) [by c(d), respectively] the greatest number such that any sequence of d-dimensional boxes [cubes, respectively] of edge length smaller than or equal to 1 and of total volume not greater than b(d) [than c(d), respectively] can be packed online into the d-dimensional unit cube (i.e., a cube of edges of length 1). In Chapter 2, I describe an algorithm for online packing of rectangles. By using this algorithm I show that b(2) is greater than or equal to 0.2837. Moreover, in Chapter 3 I prove that b(d) is not smaller than (3-2√2)·3-d for d greater than 2. In Chapter 4 I show that if n is integer not smaller than 3 and d equals 3 or 4, or if n is positive integer and d is greater than 4, then any sequence of d-dimensional cubes of edge lengths not greater than 1 whose total volume does not exceed (n+1) ·2-d can be online packed into n unit d-dimensional cubes. In Chapter 5 I show that this result holds true also for n = 1 and d = 4, i.e., c(4) is greater than or equal to 1/8. This is the crucial result in the dissertation. In chapter 6 I give results (without proofs) regarding the bin packing problem
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
Translative packing of a convex body by sequences of its homothetic copies
Get PDFsummary:Every sequence of positive or negative homothetic copies of a planar convex body whose total area does not exceed times the area of can be translatively packed in
On-line packing regular boxes in the unit cube
Get PDFsummary:We describe a class of boxes such that every sequence of boxes from this class of total volume smaller than or equal to 1 can be on-line packed in the unit cube
Translative Packing of Unit Squares Into Equilateral Triangles Some New Results On Information Transmission Over Noisy Channels
No full textEvery collection of n (arbitrary-oriented) unit squares can be packed translatively into any equilateral triangle of side length 2:3755· √n
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
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