Ostrovska, Sofiya
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Name Variants
Ostrovska, Sofıya
Ostrovska,S.
Ostrovska, Sofia
S., Ostrovska
S.,Ostrovska
O., Sofiya
Ostrovska, S
Sofiya, Ostrovska
Ostrovska, S.
Ostrovska, Sofiya
Ostrovska S.
O.,Sofiya
Ostrovska,S.
Ostrovska, Sofia
S., Ostrovska
S.,Ostrovska
O., Sofiya
Ostrovska, S
Sofiya, Ostrovska
Ostrovska, S.
Ostrovska, Sofiya
Ostrovska S.
O.,Sofiya
Job Title
Profesor Doktor
Email Address
sofia.ostrovska@atilim.edu.tr
Main Affiliation
Mathematics
Status
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
103
Articles
96
Citation Count
765
Supervised Theses
1
103 results
Scholarly Output Search Results
Now showing 1 - 10 of 103
Article Citation - WoS: 8Citation - Scopus: 10On the Image of the Limit q-bernstein Operator(Wiley, 2009) Ostrovska, Sofiya; MathematicsThe limit q-Bernstein operator B-q emerges naturally as an analogue to the Szasz-Mirakyan operator related to the Euler distribution. Alternatively, B-q comes out as a limit for a sequence of q-Bernstein polynomials in the case 0Article Citation - WoS: 125Citation - Scopus: 134Convergence of Generalized Bernstein Polynomials(Academic Press inc Elsevier Science, 2002) Il'inskii, A; Ostrovska, S; MathematicsLet f is an element of C[0, 1], q is an element of (0, 1), and B-n(f, q; x) be generalized Bernstein polynomials based on the q-integers. These polynomials were introduced by G. M. Phillips in 1997. We study convergence properties of the sequence {B-n(f, q; x)}(n=1)(infinity). It is shown that in general these properties are essentially different from those in the classical case q = 1. (C) 2002 Elsevier Science (USA).Article Citation - WoS: 2Citation - Scopus: 2HOW DO SINGULARITIES OF FUNCTIONS AFFECT THE CONVERGENCE OF q-BERNSTEIN POLYNOMIALS?(Element, 2015) Ostrovska, Sofiya; Ozban, Ahmet Yasar; Turan, Mehmet; MathematicsIn this article, the approximation of functions with a singularity at alpha is an element of (0, 1) by the q-Bernstein polynomials for q > 1 has been studied. Unlike the situation when alpha is an element of (0, 1) \ {q(-j)} j is an element of N, in the case when alpha = q(-m), m is an element of N, the type of singularity has a decisive effect on the set where a function can be approximated. In the latter event, depending on the types of singularities, three classes of functions have been examined, and it has been found that the possibility of approximation varies considerably for these classes.Article Citation - WoS: 8Citation - Scopus: 10The Norm Estimates for The q-bernstein Operator in The Case q > 1(Amer Mathematical Soc, 2010) Wang, Heping; Ostrovska, Sofiya; MathematicsThe q-Bernstein basis with 0 < q < 1 emerges as an extension of the Bernstein basis corresponding to a stochastic process generalizing Bernoulli trials forming a totally positive system on [0, 1]. In the case q > 1, the behavior of the q-Bernstein basic polynomials on [0, 1] combines the fast increase in magnitude with sign oscillations. This seriously complicates the study of q-Bernstein polynomials in the case of q > 1. The aim of this paper is to present norm estimates in C[0, 1] for the q-Bernstein basic polynomials and the q-Bernstein operator B-n,B-q in the case q > 1. While for 0 < q <= 1, parallel to B-n,B-q parallel to = 1 for all n is an element of N, in the case q > 1, the norm parallel to B-n,B-q parallel to increases rather rapidly as n -> infinity. We prove here that parallel to B-n,B-q parallel to similar to C(q)q(n(n-1)/2)/n, n -> infinity with C-q = 2 (q(-2); q(-2))(infinity)/e. Such a fast growth of norms provides an explanation for the unpredictable behavior of q-Bernstein polynomials (q > 1) with respect to convergence.Conference Object Citation - Scopus: 0Non-Asymptotic Norm Estimates for the Q-Bernstein Operators(Springer New York LLC, 2013) Ostrovska,S.; Özban,A.Y.; MathematicsThe aim of this paper is to present new non-asymptotic norm estimates in C[0,1] for the q-Bernstein operators Bn,q in the case q > 1. While for 0 < q ≤ 1, {double pipe}Bn,q{double pipe} = 1 for all n ∈ ℕ, in the case q > 1, the norm {double pipe}Bn,q{double pipe} grows rather rapidly as n → + ∞ and q → + ∞. Both theoretical and numerical comparisons of the new estimates with the previously available ones are carried out. The conditions are determined under which the new estimates are better than the known ones. © Springer Science+Business Media New York 2013.Article Citation - WoS: 0Citation - Scopus: 0Norming Subspaces Isomorphic to l1(Springer Heidelberg, 2015) Ostrovska, Sofiya; MathematicsNorming subspaces are studied widely in the duality theory of Banach spaces. These subspaces are applied to the Borel and Baire classifications of the inverse operators. The main result of this article asserts that the dual of a Banach space X contains a norming subspace isomorphic to l(1) provided that the following two conditions are satisfied: (1) X* contains a subspace isomorphic to l(1); and (2) X* contains a separable norming subspace.Article Citation - WoS: 5Citation - Scopus: 5Analytical Properties of the Lupas q-transform(Academic Press inc Elsevier Science, 2012) Ostrovska, Sofiya; MathematicsThe Lupas q-transform emerges in the study of the limit q-Lupas operator. The latter comes out naturally as a limit for a sequence of the Lupas q-analogues of the Bernstein operator. Given q is an element of (0, 1), f is an element of C left perpendicular0, 1right perpendicular, the q-Lupas transform off is defined by (Lambda(q)f) (z) := 1/(-z; q)(infinity) . Sigma(infinity)(k=0) f(1 - q(k))q(k(k -1)/2)/(q; q)(k)z(k). The transform is closely related to both the q-deformed Poisson probability distribution, which is used widely in the q-boson operator calculus, and to Valiron's method of summation for divergent series. In general, Lambda(q)f is a meromorphic function whose poles are contained in the set J(q) := {-q(-j)}(j=0)(infinity). In this paper, we study the connection between the behaviour of f on leftperpendicular0, 1right perpendicular and the decay of Lambda(q)f as z -> infinity. (C) 2012 Elsevier Inc. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Personal Response Systems Through the Prism of Students' Experiences(Wiley, 2020) Mishra, Deepti; Chew, Esyin; Ostrovska, Sofiya; Wong, Jojo; Mathematics; Computer EngineeringPersonal response systems (PRSs) today offer an opportunity to the field of education in terms of improving teaching and learning outcomes through active engagement in classrooms. The present paper investigates students' attitudes to different types of PRSs, namely, Socrative and Clickers. Both qualitative and quantitative data are gathered and classified. The performed thematic analysis reveals major categories within the framework of this study, namely educational efficacy, psychological aspects, technology-related issues, and administrative issues. It has been found that Socrative fares better in the "educational efficacy" and "administrative issues," whereas Clickers outperforms Socrative in the "technological-related issues." It is worth pointing out that both Socrative and Clickers are tantamount in "psychological aspects" yielding no negative experiences. The results of this study reveal that two main factors, cost and technological infrastructure, are determinative in the incorporation and appreciation of such systems in an educational setting.Article Citation - WoS: 11Citation - Scopus: 12Assessing Team Work in Engineering Projects(Tempus Publications, 2015) Mishra, Deepti; Ostrovska, Sofiya; Hacaloglu, Tuna; Mathematics; Computer Engineering; Information Systems Engineering; Mathematics; Computer Engineering; Information Systems EngineeringTeam work is considered a valuable teaching technique in higher education. However, the assessment of an individual's work in teams has proved to be a challenging task. Consequently, self-and peer-evaluations are becoming increasingly popular for the assessment of individuals in a team work, though it is essential to determine whether students can judge their own as well as their peer's performance effectively. Self-and peer-evaluations have been applied in different disciplines and their authenticity with regard to teacher's assessment has been evaluated in the literature but this issue has not been investigated in the field of engineering education so far. In this study, a peer-and self-assessment procedure is applied to the evaluation of a project work conducted in teams of 3 or 4 students. The participants were engineering students taking two similar courses related with database design and development. It is found that a majority of the students were unable to assess themselves as objectively as their instructor. Further, it is observed that successful students tend to under-estimate, whereas unsuccessful students tend to over-estimate, their own performance. The paper also establishes that the results of self-assessments are independent from the gender factor.Article Citation - WoS: 2Citation - Scopus: 2On the q-bernstein Polynomials of Piecewise Linear Functions in the Case q > 1(Pergamon-elsevier Science Ltd, 2013) Kaskaloglu, Kerem; Ostrovska, Sofiya; MathematicsThe aim of this paper is to present new results related to the approximation of continuous functions by their q-Bernstein polynomials in the case q > 1. The first part of the paper is devoted to the behavior of the q-Bernstein polynomials of piecewise linear functions. This study naturally leads to the notion of truncated q-Bernstein polynomials introduced in the paper. The second part deals with the asymptotic estimates for the norms of the m-truncated q-Bernstein polynomials, in the case where both n and q vary. The results of the paper are illustrated by numerical examples. (C) 2012 Elsevier Ltd. All rights reserved.
