# Communications, Series A1:Mathematics and Statistics

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Item [1,2]-Complementary connected domination number of graphs-III(Ankara Üniversitesi Fen Fakültesi, 2019-08-01) Mahadevan, G.; Renuka, K.; Other; OtherShow more A set S⊆V(G) in a graph G is said to be [1,2]-complementary connected dominating set if for every vertex v∈V-S, 1≤|N(v)∩S|≤2 and is connected. The minimum cardinality of [1,2]-complementary connected dominating set is called [1,2]-complementary connected domination number and is denoted by γ_{[1,2]cc}(G). In this paper, we investigate 3-regular graphs on twelve vertices for which γ_{[1,2]cc}(G)=χ(G)=3.Show more Item A characteristic property of a developable surfaceSABAN, GiacomoShow more Item A CHARACTERIZATION OF CYLINDRICAL HELIX STRIPKAYA, Filiz ErtemShow more Item A Characterization of Inclined Curves in Euclidean n-SpaceÖZDAMAR, E;HACISALİHOĞLU, H.H.Show more Item A class of meromorphic univalent functions with positive and fixed finitely many coefficientsAOUF, M. K.;HOSSEN, H. M.Show more Item A Class Of Ovoidal Laguerre PlanesKAYA, RüstemShow more Item A class of submersions and compatible maps in Finsler geometry(Ankara Üniversitesi Fen Fakültesi, 2019-02-01) Crasmareanu, Mircea; Other; OtherShow more We introduce a class of submersions between two Finslerian manifolds and the class of Finsler-compatible maps which contains the previous class. Defining also the notion of stretch it follows an upper bound for the stretch of these submersions. If the support manifold for the considered Finslerian geometries is the same we introduce a new function, called conformality, as a way to measure quantitatively the difference between the given geometries.Show more Item A classification of ( k , μ ) ′ -almost Kenmotsu manifolds admitting Cotton tensor(Ankara Üniversitesi Fen Fakültesi, 2021-06-30) DEY, Dibakar; MAJHİ, Pradip; Other; OtherShow more The object of the present paper is to classify ( k , μ ) ′ -almost Kenmotsu manifolds admitting Cotton tensors. We characterize ( k , μ ) ′ -almost Kenmotsu manifolds with vanishing and parallel Cotton tensors. Beside this, ( k , μ ) ′ -almost Kenmotsu manifolds satisfying Cotton semisymmetry and Q ( g , C ) = 0 are studied. Further, Cotton pseudo-symmetric ( k , μ ) ′ -almost Kenmotsu manifolds are classified.Show more Item 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; OtherShow more 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.Show more Item A comparative study of classifiers for early diagnosis of gestational Diabetes Mellitus(Ankara Üniversitesi Fen Fakültesi, 2020-06-30) Muller, Priya Shirley; Nirmala, M.; Other; OtherShow more Gestational Diabetes Mellitus (GDM), usually found deploying a medical test called the Oral Glucose Tolerance Test (OGTT), is a prevalent complication during pregnancy. Early detection of GDM and identifying the most influential risk factors of GDM pose to be a challenging problem and is found to be crucial as GDM has dreadful health indications for both mother and the baby. The performances of computational techniques like Radial Basis Function (RBF) neural network and Multilayer Perceptron Network (MLP) were collated with that of the statistical technique Discriminant Analysis (DA) on real time GDM datasets for diagnosis of GDM in multigravida pregnant women, specifically women who have been pregnant more than once, without even a visit to the hospital. The most influential risk factors were identified using DA while the overall performance of MLP beyond doubt established itself to be the most effective technique for early diagnosis of GDM in women during pregnancy.Show more Item 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; OtherShow more 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.Show more Item A comparison of different methods of estimation for the flexible Weibull distribution(Ankara Üniversitesi Fen Fakültesi, 2020-06-30) Ali, Sajid; Dey, Sanku; Tahir, M. H.; Mansoor, Muhammad; Other; OtherShow more This article presents different parameter estimation methods for flexible Weibull distribution introduced by Bebbington et al. (Reliability Engineering and System Safety 92:719-726, 2007), which is a modified version of the Weibull distribution and is suitable to model different shapes of the hazard rate. We consider both frequentist and Bayesian estimation methods and present a comprehensive comparison of them. For frequentist estimation, we consider the maximum likelihood estimators, least squares estimators, weighted least squares estimators, percentile estimators, the maximum product spacing estimators, the minimum spacing absolute distance estimators, the minimum spacing absolute log-distance estimators, Cramér von Mises estimators, Anderson Darling estimators, and right tailed Anderson Darling estimators, and compare them using a comprehensive simulation study. We also consider Bayesian estimation by assuming gamma priors for both shape and scale parameters. We use a Markov Chain Monte Carlo algorithm to compute the posterior summaries. A real data example is also a part of this work.Show more Item A Comparison of Gauss-MarkovEstimators and Least Squares Estimatorsof the Micro and Macro ParametersAKDENİZ, F;MILLIKEN, G. A.Show more Item A computational method for integro-differential hyperbolic equation with integral conditionsMERAD, Ahcene; BOUZIANI, AbdelfatahShow more Item A convergence theorem in generalized convex cone metric spacesGÜNDÜZ, BirolShow more Item A convexity study in sphereBELTAGY, M.Show more Item A correction on tangentboost algorithmTOKA, Onur; ÇETİN, MeralShow more Item A criterion for restricted ideal sheaves and on regular covering spacesULUÇAY, CengizShow more Item A data science study for determining food quality: an application to wine(Ankara Üniversitesi Fen Fakültesi, 2019-02-01) Özalp, Ata Emre; Askerzade, İman; Bilgisayar Mühendisliği; Mühendislik FakültesiShow more In this paper, wine quality is investigated based on physicochemical ingredients which include fixed acidity, volatile acidity, citric acid, residual sugar, chloride, free sulfur dioxide, total sulfur dioxide, density, pH, sulphate and alcohol, by ANFIS (Adaptive Neuro Fuzzy Inference System) method and by random forest algorithm which is a powerful classification algorithm. Although this study specifically investigate the relation between physicochemical ingredients and the quality of wine, the results can be adaped to determination of the quality of any food product in terms of the ingredients.Show more