1,720,982 research outputs found
A Fractional-Order Mathematical Model to Analyze the Stability and Develop a Sterilization Strategy for the Habitat of Stray Dogs
No full textBilgil, Halis/0000-0002-8329-5806; Yousef, Ali/0000-0002-8824-5947; Sorgun, Sezer/0000-0001-8708-1226; Ozturk, Zafer/0000-0001-5662-4670;Today, the socio-cultural lack of some countries with increased urbanization has led to the unconscious breeding of stray dogs. The failure to care for the offspring of possessive dogs or ignoring the responsibility to find a suitable family for the offspring increased the dog population on the streets and in the shelters. In this study, our main target is to analyze the habitat of stray dogs and the strategy of how to control the population without damaging the ecosystem of the species. For this aim, we establish a fractional-order differential equation system to investigate the fractal dimension with long-term memory that invovles two compartments; the non-sterilized dog population (x(t)) and the sterilized one (y(t)). Firstly, we analyze the stability of the equilibrium points using the Routh-Hurwitz criteria to discuss cases that should not affect the ecosystem of the dog population, but control the stray dog population in the habitat. Since the intervention to the stray dog population occurs at discrete time impulses, we use the Euler method's discretization process to analyse the local and global stability around the equilibrium points. Besides this, we show that the solutions of the system represent semi-cycle behaviors. At the end of the study, we use accurate data to demonstrate the sterilization rate of stray dogs in their habitat
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
Consta-cyclic codes
No full textBu tezde ele alınan konular genel itibari ile "J. Qian, Li Zhang, Shi Zhu,Constacyclic and cyclic codes over〖 F〗_2+uF_2+u^2 F_2, Oxfored Journals Mathematics and Physical Sciences IEICE-Tran Fund Elec, Command Comp Sci E89-A, 6, 2006. 1863-1865" ve "Jian-Fa Qian, Li-Na Zhang and Shi-Xin Zhu,(1+u)-constacyclic and cyclic overF_2+uF_2, Applied Mathematics Letters, 19 (18) 2006, 820-823" makalelerinden derlenmiştir. Tezin birinci bölümünde kodlamanın doğuşu ve amacı ile ilgili bilgiler, ikinci bölümünde kodlama teorisi ile ilgili temel tanım ve kavramlar verilmiştir. Üçüncü bölümde, sonlu zincir halkaları üzerindeki konsta-devirli kodlar ele alınmıştır.Z_4 üzerinde n uzunluğunda bir lineer konsta-devirli kodun Gray görüntüsünün bir ikili uzaklığa sahip değişmez devirli kod olduğu veR_2=F_2+uF_2 ve R_3=F_2+uF_2+u^2 F_2 üzerinde sırası ile (1+u)-konsta devirli ve (1-u^2)-konsta-devirli kodların genel tanımları verilmiştir.The topics discussed in this thesishas generally been compiled from"J. Qian, Li Zhang, Shi Zhu,Constacyclic and cyclic codes over〖 F〗_2+uF_2+u^2 F_2, Oxfored Journals Mathematics and Physical Sciences IEICE-Tran Fund Elec, Command Comp Sci E89-A, 6, 2006. 1863-1865" and "Jian-Fa Qian, Li-Na Zhang and Shi-Xin Zhu, constacyclic and cyclic overF_2+uF_2, Applied Mathematics Letters, 19 (18) 2006, 820-823" references. In the first section of this thesis some information about the starting of coding is given. In the second section, The basic definitions and concepts related to coding theory is determined. The third section of the thesisis deal with consta-cyclic codes over finite chain rings. Especially, Gray image of a linear constacyclic code over Z_4 of lenght n is a binary distance invariant cyclic code. Also constacyclic and (1-u^2)-constacyclic code over the ring R_2=F_2+uF_2 and R_3=F_2+uF_2+u^2 F_2is introduced
The eccentricity matrix of graphs and its spectra
No full textGünümüzde çizge kuramı, hem teorik (kuramsal) hem de pratik düzeyde yalnızca muazzam büyüklükte değil, aynı zamanda olağanüstü zenginlik ve karmaşıklık ile karşımıza çıkar. Matematiksel Kimya alanında önemli katkıları bulunan Milan Randić, 2013 yılında ilginç bir makale kaleme almıştır. Bu makale ile kimyada moleküler tanımlayıcılar olarak isimlendirilen kavramların çizge değişmezleri ile ifade edilmelerine olanak sağlamıştır. Aslında tanımlanan matris dışmerkezlilik (zıt komşuluk) matrisidir. Bu bakış açısı ile birlikte komşuluk ve dışmerkezlilik matrisleri mesafe temelli çizge matris ailesi içerisinde uç bölgelerde yer alır (min-maks ilişkisi). Çizge matrisleri üzerine çalışma yapan her araştırmacının karşılaştığı komşuluk ve mesafe matrisleri spektral çizge kuramında geniş bir çalışma sahasına sahiptir. Bu tez çalışmasında çizge kuramının çoklu disiplinler açısından önemi, dışmerkezlilik matrisinin çizge-mesafe sorunsalı, spektral çizge kuramı içerisindeki yeri ve spektral karakterizasyon çalışması yapılmıştır. 2, 3 ve 4. bölümlerde Çizge Kuramı ve Spektral Çizge Kuramı ile ilgili temel tanım ve kavramlar etimolojik olarak belli bir düzene göre geniş bir biçimde verilmiştir. 5. bölümde dışmerkezlilik matrisi ile ilgili spektral çalışmalar kronolojik olarak sıralanmıştır. Ayrıca tarafımızdan literatüre kazandırılan özgün sonuçlar alt bölümde detaylı olarak verilmiştir. 6. bölümde açık problemler, gözlemler ve yorumlara dair varsayımlar yer almaktadır.Graph theory today appears not only of enormous magnitude, but also of extraordinary richness and complexity, both on a theoretical and practical level. Milan Randić, who has made important contributions to the field of Mathematical Chemistry, has written an interesting article in 2013. With this article, it has enabled the concepts called molecular descriptors in chemistry to be expressed with graph invariants. Actually, the defined matrix is the eccentricity (anti-adjacency) matrix. With this point of view, adjacency and eccentricity matrices are located in the extreme regions of the distance-based graph matrix family (in terms of minimum and maximum). Adjacency and distance matrices encountered by every researcher working on graph matrices have a wide field of study in spectral graph theory. In this thesis, the importance of graph theory in terms of multi-disciplines, the graph-distance problem of the eccentricity matrix, its place in spectral graph theory and spectral characterization studies have been presented. In chapters 2, 3 and 4, basic definitions and concepts related to Graph Theory and Spectral Graph Theory are given in a broad etymological order. In Chapter 5, spectral studies on the eccentricity matrix are listed chronologically. Also, the original results, which has been brought to the literature by us, are given in detail in the subsection. Chapter 6 contains open problems, observations and conjectures related to the eccentricity matrix
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
Numerical solutions of some linear and nonlinear ordinary differential equations by successive complementary expansion method
No full textMatematik problemleri, fiziksel olayların matematiksel modellemesidir. Bu problemlerin tam çözümlerinin bulunabilmesi her zaman mümkün olmamaktadır. Çözümler için bilgisayar kullanımının yanı sıra asimptotik açılımlar yardımıyla yaklaşım sağlanabilir. Ancak asimptotik açılımlar geçtiğimiz yüzyıldan bu yana uygulamalı matematik, mühendislik bilimleri ve özellikle akışkanlar mekaniğinde önemli yer tutmaktadır. Yaklaşım metotları arasında başta gelen metot, pertürbasyon (asimptotik) metodudur. Bu tekniğe göre çözüm bir asimptotik açılımın ilk birkaç terimi tarafından sunulur. Bu tezde genelleştirilmiş asimptotik genişlemelere dayanan ardışık tümler açılım metodu (SCEM) adı verilen etkili bir yöntem kullanıldı. İyi bilinen yöntem eşleştirilmiş asimptotik açılımlar metodu (MMAE) nin aksine, SCEM ile daha geçerli yaklaşımlar elde edildi. MMAE yöntemine göre SCEM ile tam çözüme daha yakın çözümler elde edildi. Bu tez çalışmasının asıl amacı diferansiyel denklemlerin çözümlerine asimptotik yaklaşımlar oluşturmaktır. Ardışık tümler açılım metodu ile verilen adi diferansiyel denklemlerin çözümlerine yakın sonuçlar ile birlikte yöntemin etkinliği bazı sayısal denemeler, tam çözümler ve MMAE gibi diğer mevcut yöntemlerle karşılaştırmalar yoluyla gösterilmiştir. Yöntemin işleyişi, örnekler üzerinde ayrıntılı olarak derlendi. Bunun için öncelikle eşleştirilmiş açılımlar metodunun (MMAE) üzerinde duruldu, daha sonra ardışık tümler açılım metodu (SCEM) ayrıntılı olarak incelendi. Sonuç olarak, SCEM yönteminin MMAE yöntemine göre daha avantajlı ve tam çözüme daha yakın sonuçlar elde edildiği görüldü.Mathematical problems are mathematical modeling of physical phenomena. It is not always possible to find exact solutions of these problems. Solutions can be accessed by using asymptotic expansions as well as computer usage. However, asymptotic expansions have played an important role in applied mathematics, engineering sciences, and fluid mechanics since the past century. The main method of approach is the perturbation (asymptotic) method. According to this method the solution is presented by the first few terms of an asymptotic expansion. In this thesis, an effective method called Successive Complementary Expansion Method (SCEM) based on generalized asymptotic expansions was used. Unlike the well-known Method of Matched Asymptotic Expansions (MMAE), more valid approaches were obtained with SCEM. According to the MMAE method, exact solutions were obtained with SCEM. The main purpose of this thesis is to develop asymptotic approaches to the solution of differential equations. The efficiency of the method, along with the results close to the solutions of the ordinary differential equations given by the consecutive solutions method, has been demonstrated by comparison with some existing numerical experiments, exact solutions and other existing methods such as MMAE. The function of the method has been compiled in detail on the samples. For this, the MMAE was firstly emphasized, then the successive method of opening all the scales SCEM was examined in detail. As a result, it is abserved that the SCEM method was more advantageous than the MMAE method and more exact solution was obtained
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
On the bounds for the largest Laplacian eigenvalues of weighted graphs
Get PDFWOS: 000304736800006We consider weighted graphs, such as graphs where the edge weights are positive definite matrices. The Laplacian eigenvalues of a graph are the eigenvalues of the Laplacian matrix of a graph G. We obtain an upper bound for the largest Laplacian eigenvalue and we compare this bound with previously known bounds. (C) 2012 Elsevier B.V. All rights reserved
Algebraic properties of total graphs
No full textÇizgi çizgeler olarak da bilinen total çizgeler, köşelerin kenarlarla ilişkilendirilmesiyle orijinal çizgeden elde edilir. Toplam çizgedeki her kenar, orijinal çizgedeki iki kenar arasındaki komşuluğu temsil eder. Bu dönüşüm, orijinal çizgenin yapısal ve bağlantısal özelliklerinin farklı bir bağlamda keşfedilmesini kolaylaştırır. Bu tez çalışmasının 2. Bölümünde çizge teorisi ile ilgili bazı temel tanım ve kavramlar verilmiştir. Ayrıca bu bölümde total çizgeler tanıtılmış ve bazı çizge parametreleri ile ilişkileri verilmiştir. 3. Bölümde ise halka yapıları üzerinde inşa edilen total çizgelerin cebirsel özellikleri derlenmiştir.Total graphs, also known as line graphs, are obtained from the original graph by associating vertices with edges. Each edge in the aggregate graph represents a neighborhood between two edges in the original graph. This transformation facilitates exploration of the structural and connectivity properties of the original graph in a different context. In Chapter 2 of this thesis, some basic definitions and concepts related to graph theory are given. Additionally, in this section, total graphs are introduced and their relationships with some graph parameters are given. In Chapter 3, the algebraic properties of total graphs built on ring structures are compiled
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