Cilt:69 Sayı:02 (2020)

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https://dspace.ankara.edu.tr/handle/20.500.12575/76048

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A common fixed point theorem for multi-valued θ_{δ} contractions via subsequential continuity
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Ahmed, Ali; MAHİDEB, Saadia; BELOUL, Said; Other; Other
The main objective of this paper is to present a common fixed point theorem for two pairs of single and set valued mappings via subsequential continuity and \delta- compatibility. To illustrate the validity of our results, an example is provided and we give also an application for a system of integral inclusions of Volterra type.
A comparative study on the performance of frequentist and Bayesian estimation methods under separation in logistic regression
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Altınışık, Yasin; Other; Other
Separation is one of the most commonly encountered estimation problems in the context of logistic regression, which often occurs with small and medium sample sizes. The method of maximum likelihood (MLE; Fisher) provides spuriously high parameter estimates and their standard errors under separation in logistic regression. Many researchers in social sciences utilize simple but ad-hoc solutions to overcome this issue, such as "doing nothing strategy", removing variable(s) from the model, and combining the levels of the categorical variable in the data causing separation etc. The limitations of these basic solutions have motivated researchers to use more appropriate and innovative estimation techniques to deal with the problem. However, the performance and comparison of these techniques have not been fully investigated yet. The main goal of this paper is to close this research gap by comparing the performance of frequentist and Bayesian estimation methods for coping with separation. A simulation study is performed to investigate the performance of asymptotic, bootstrap-based, and Bayesian estimation techniques with respect to bias, precision, and accuracy measures under separation. In line with the simulation study, a real-data example is used to illustrate how to utilize these methods to solve separation in logistic regression.
A new class of generating functions of binary products of Gaussian numbers and polynomials
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) BOUGHABA, Souhila; BOUSSAYOUD, Ali; KERADA, Mohamed; Other; Other
In this paper, we introduce a operator in order to derive some new symmetric properties of Gaussian Fibonacci numbers and Gaussian Lucas numbers. By making use of the operator defined in this paper, we give some new generating functions for Gaussian Fibonacci numbers and Gaussian Jacobsthal polynomials. In the paper Al4, Al5, a second-order linear recurrence sequence (U_{n}(a,b;p,q))_{n≥0} or briefly (U_{n})_{n≥0} is considered by the recurrence relation: U_{n+2}=pU_{n+1}+qU_{n}, with the initial conditions U₀=a and U₁=b, where a,b∈ℂ and p,q∈ℤ₊ for n≥0.
A new generalized-upper record values-G family of lifetime distributions
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Kharazmi, Omid; Saadatinik, Ali; Hamedami, G.; Other; Other
A new family of lifetime distributions is introduced via distribution of the upper record values, the well-known concept in survival analysis and reliability engineering. Some important properties of the proposed model including quantile function, hazard function, order statistics are obtained in a general setting. A special case of this new family is proposed by considering the exponential and Weibull distribution as the parent distributions. In addition estimating unknown parameters of specialized distribution is examined from the perspective of the traditional statistics. A simulation study is presented to investigate the bias and mean square error of the maximum likelihood estimators. Moreover, one example of real data set is studied; point and interval estimations of all parameters are obtained by maximum likelihood and bootstrap (parametric and non-parametric) procedures. Finally, the superiority of the proposed model in terms of the parent exponential distribution over other known distributions is shown via the example of real observations.
A note on quasi bi-slant submanifolds of cosymplectic manifolds
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Akyol, Mehmet Akif; Beyendi, Selahattin; Other; Other
The aim of the present paper is to define and study the notion of quasi bi-slant submanifolds of almost contact metric manifolds. We mainly concerned with quasi bi-slant submanifolds of cosymplectic manifolds as a generalization of slant, semi-slant, hemi-slant, bi-slant and quasi hemi-slant submanifolds. First, we give non-trivial examples in order to demostrate the method presented in this paper is effective and investigate the geometry of distributions. Moreover, We study these types of submanifolds with parallel canonical structures.
A solution of a viscosity Cesàro mean algorithm
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) SAHEBİ, Hamid Reza; Other; Other
Based on the viscosity approximation method, we introduce a new cesaro mean approximation method for finding a common solution of split generalized equilibrium problem in real Hilbert spaces. Under certain conditions control on parameters, we prove a strong convergence theorem for the sequences generated by the proposed iterative scheme. Some numerical examples are presented to illustrate the convergence results. Our results can be viewed as a generalization and improvement of various existing results in the current literature.
A subclass of pseudo-type meromorphic bi-univalent functions
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Alamoush, Adnan; Other; Other
In this paper, In the present article, a new subclass of pseudo-type meromorphic bi-univalent functions is defined on △={z |:z∈C and 1<|z|<∞}, we derive estimates on the initial coefficient |b₀|, |b₁| and |b₂|. Relevant connections of the new results with various well-known results are indicated. Motivated by the earlier work of (Srivastava, Janani), in the present paper, we introduce a new subclasses of the class Σ′ and the estimates for the coefficients |b₀|,|b₁| and |b₂| are investigated. Some new consequences of the new results are also pointed out.
A-statistically localized sequences in n-normed spaces
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Gürdal, Mehmet; Sarı, Nur; Savaş, Ekrem; Other; Other
In 1974, Krivonosov defined the concept of localized sequence that is defined as a generalization of Cauchy sequence in metric spaces. In this present work, the A-statistically localized sequences in n-normed spaces are defined and some main properties of A-statistically localized sequences are given. Also, it is shown that a sequence is A-statistically Cauchy iff its A-statistical barrier is equal to zero. Moreover, we define the uniformly A-statistically localized sequences on n-normed spaces and investigate its relationship with A-statistically Cauchy sequences.
Almost contact metric and metallic Riemannian structures
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Gherici, Beldjilali; Other; Other
The metallic structure is a fascinating topic that continually generates new ideas. In this work, new metallic manifolds are constructed starting from both almost contact metric manifolds and we obtain some important notions like the metallic deformation. We show that there exists a correspondence between the metallic Riemannian structures and the almost contact metric structures. We give an open question where we propose the first step to study the reverse, i.e. the construction of an almost contact metric structure starting from a metallic Riemannian structure. We give a concrete example to confirm this construction.
An adaptive extended Kalman filtering approach to nonlinear dynamic gene regulatory networks via short gene expression time series
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Özbek, Levent; İstatistik; Fen Fakültesi
Gene regulation is one of the most amazing processes in which living cells are involved. Different genes may cooperate to produce a particular reaction if more than one genes are suppressed by a gene. The gene triggers a certain genetic disease, for instance, through inactivating the gene that is responsible for cancer, the disease produced by this gene may be controlled. Gene control and interaction might be defined by a gene regulatory network. DNA microarray technology has provided an efficient method for evaluating expression levels of thousands of genes in a single experiment. It enables to trace the levels of the expression of thousands of genes at once. Evaluating gene expression levels may be beneficial for medical diagnosis, treatment and drug design in different circumstances. With an intent to understand the effective biological data and to identify the connections between the individual genes, most of the current research efforts are focused on clustering. Recently, remodelling of the gene regulatory networks over the data on the time series has become an increasing field of interest. As a matter of fact, choosing a good model for the gene regulatory networks is required for a significant data analysis. Several gene expression experiments produce data on short time series only on a few points in time due to the high costs of the evaluation. Time series generally represent the dynamic responses to, some medicines or other treatment methods. As a consequence, modelling the time series of the gene expressions which is needed to pick the functional information over the data on time series has become an increasingly interesting field of study. Since gene regulatory networks form a naturally stochastic structure, the observed data on the time series may be modelled by using non-linear stochastic state space models and the parameters included in the model may be estimated with the Extended Kalman Filter (EKF) method. There have been many studies regarding this topic made in the literature. However, the fact that the model is nonlinear may cause some problems on the estimations of Kalman Filter (KF) method. For this reason, the researches on the adaptive methods in the EKF are going on with the aim of supporting the estimations. In this research, application of the developed model on the gene regulatory networks has been examined. With the aim of corroborating estimation method, it has been decided that the adaptive extended Kalman Filter (AEKF) was proper for being used and malaria gene expression has been applied for the set of data on the time series. A results have been compared with the results of the former research [1], and it has been understood that the estimation results obtained through the developed model were more preferable.
An approach to pre-separation axioms in neutrosophic soft topological spaces
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Açıkgöz, Ahu; Esenbel, Ferhat; Other; Other
In this study, we introduce the concept of neutrosophic soft pre-open (neutrosophic soft pre-closed) sets and pre-separation axioms in neutrosophic soft topological spaces. In particular, the relationship between these separation axioms are investigated. Also, we give a new deﬁnition for neutrosophic soft topological subspace and deﬁne neutrosophic soft pre irresolute soft and neutrosophic pre irresolute open soft functions.
Analysis of fractional differential systems involving Riemann Liouville fractional derivative
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Batik, Songül; Deren, Fulya Yörük; Other; Other
This paper is devoted to studying the multiple positive solutions for a system of nonlinear fractional boundary value problems. Our analysis is based upon the Avery Peterson fixed point theorem. In addition, we include an example for the demonstration of our main result.
Annihilators of power values of b-generalized derivations in prime rings
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Yarbil, Nihan Baydar; Other; Other
Let R be a prime ring with extended centroid C and maximal left ring of quotients Q m l ( R ) . For a nonzero element b ∈ R let F : R → R be a right generalized b -derivation associated with the map d of R . Suppose that s ( F ( x ) ) n = 0 for all x ∈ R where s is a nonzero element in R and n ≥ 1 is a fixed positive integer. Then there exist some c ∈ Q m l ( R ) and β ∈ C such that d ( x ) = a d c ( x ) , F ( x ) = ( b + β ) x b for all x ∈ R and either s ( c + β ) = 0 or b ( c + β ) = 0 .
Approximation by Bézier variant of Jakimovski-Leviatan-Păltănea operators involving Sheffer polynomials
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) AGRAWAL, P.; KUMAR, Ajay; Other; Other
In the present paper, the Bezier variant of Jakimovski-Leviatan-Peltenea operators involving Sheffer polynomials is introduced and the degree of approximation by these operators is investigated with the aid of Ditzian-Totik modulus of smoothness, Lipschitz type space and for functions with derivatives of bounded variations.
Best proximity problems for new types of Z -proximal contractions with an application
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Işık, Hüseyin; Aydi, Hassen; Other; Other
In this study, we establish existence and uniqueness theorems of best proximity points for new types of Z -proximal contractions defined on a complete metric space. The presented results improve and generalize some recent results in the literature. Several examples are constructed to demonstrate the generality of our results. As applications of the obtained results, we discuss sufficient conditions to ensure the existence of a unique solution for a variational inequality problem.
Digital Hausdorff distance on a connected digital image
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Vergili, Tane; Other; Other
A digital image X can be considered as a subset of Zⁿ together with an adjacency relation where Z is the set of the integers and n is a natural number. The aim of this study is to measure the closeness of two subsets of a connected digital image. To do this, we adapt the Hausdorff distance in the topological setting to its digital version. In this paper, we define a metric on a connected digital image by using the length of the shortest digital simple path. Then we use this metric to define the r-thickening of the subsets of a connected digital image and define the digital Hausdorff distance between them.
Equitable edge coloring on tensor product of graphs
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) VENİNSTİNE, Vivik J; AKBAR ALI, M. M.; GIRIJA, G.; Other; Other
A graph G is edge colored if different colors are assigned to its edges or lines, in the order of neighboring edges are allotted with least diverse k-colors. If each of k-colors can be partitioned into color sets and differs by utmost one, then it is equitable. The minimum of k-colors required is known as equitably edge chromatic number and symbolized by χ ′ = ( G ) . Further the impression of equitable edge coloring was first initiated by Hilton and de Werra in 1994. In this paper, we ascertain the equitable edge chromatic number of P m ⊗ P n , P m ⊗ C n and K 1 , m ⊗ K 1 , n .
Fractional variational problems on conformable calculus
(Ankara Üniversitesi, 2021) Öğrekçi, Süleyman; Other; Other
In this paper, we deal with the variational problems defined by an integral that include fractional conformable derivative. We obtained the optimality results for variational problems with fixed end-point boundary conditions and variable end-point boundary conditions. Then, we studied on the variational problems with integral constraints and holonomic constraints, respectively.
Harary energy of complement of line graphs of regular graphs
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Ramane, Harishchandra; Ashoka, K.; Other; Other
The Harary matrix of a graph G is defined as H ( G ) = [ h i j ] , where h i j = 1 d ( v i , v j ) , if i ≠ j and h i j = 0 , otherwise, where d ( v i , v j ) is the distance between the vertices v i and v j in G . The H -energy of G is defined as the sum of the absolute values of the eigenvalues of Harary matrix. Two graphs are said to be H -equienergetic if they have same H -energy. In this paper we obtain the H -energy of the complement of line graphs of certian regular graphs interms of the order and regularity of a graph and thus constructs pairs of H -equienergetic graphs of same order and having different H -eigenvalues.
Invariant submanifolds in golden Riemannian manifolds
(Ankara Üniversitesi Fen Fakültesi, 2020-12-31) Kılıç, Erol; Gök, Mustafa; Keleş, Sadık; Other; Other
In this paper, we study invariant submanifolds of a golden Riemannian manifold with the aid of induced structures on them by the golden structure of the ambient manifold. We demonstrate that any invariant submanifold in a locally decomposable golden Riemannian manifold leaves invariant the locally decomposability of the ambient manifold. We give a necessary and sufficient condition for any submanifold in a golden Riemannian manifold to be invariant. We obtain some necessary conditions for the totally geodesicity of invariant submanifolds. Moreover, we find some facts on invariant submanifolds. Finally, we present an example of an invariant submanifold.

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