WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653

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Citation - WoS: 2
Citation - Scopus: 2
Guest Editorial: Gamification and Persuasive Games for Software Engineering
(inst Engineering Technology-iet, 2019) O'Connor, Rory V.; Colomo-Palacios, Ricardo; Clarke, Paul; Yilmaz, Murat
Citation - WoS: 10
Citation - Scopus: 15
Sources and Channels of International Knowledge Spillovers in Asean-5: the Role of Institutional Quality
(Wiley, 2020) Dogan, Ergun; Wong, Koi Nyen
Association of Southeast Asian Nations (ASEAN) is a dynamic and outward-looking regional economy, which has made notable progress in expanding trade and investment. This paper examines whether knowledge spillovers are prevalent among ASEAN-5, focusing on the issues of which channels and which sources are the potential drivers of total factor productivity. The findings reveal that the key spillover channels are exports and non-capital imports coming from source countries such as the Organisation for Economic Co-operation and Development (OECD) countries, the G7 countries. The institutional quality plays an instrumental role in increasing total factor productivity through foreign direct investment, especially when the spillovers originate from the OECD and the G7. (c) 2020 John Wiley & Sons, Ltd.
Citation - WoS: 3
Citation - Scopus: 3
Exploring Fire Safety Conditions of Double Skin Facades
(Gazi Univ, Fac Engineering Architecture, 2024) Aslar, Eylem Ezgi; Harputlugil, Gulsu Ulukavak
Human health, comfort and safety are of primary importance in the built environment. Among the security measures, the most important risk is the risk of fire. For this reason, the issue of fire risk, spread and safety is considered as one of the criteria that should be considered from the building design stage. Within the scope of this study, building models with the same floor height, different plan and facade types, designed in 3D, were analyzed in the fire simulation program called PyroSim. Based on the data obtained as a result of the analyzes, the results of the temperature, smoke and flame spread at the time of fire according to the facade and plan types are presented in tables. As a result of the data obtained, it was determined that box-type systems in double-layer facades are the most problematic facade type in terms of evacuation of living creatures. In terms of smoke spread, it has been revealed that the systems that continue uninterruptedly along the facade pose a problem when the access and spread to other floors are taken into account. It is necessary to consider fire safety as a design problem. It is considered that more detailed studies should be carried out in our country on this subject, that the project should be designed by considering the simulations from the decision stage to the implementation stage of the building, and that the regulations should be developed in order to be a good guide in both the design and implementation stages.
Citation - Scopus: 2
Quadruple Best Proximity Points With Applications To Functional and Integral Equations
(Wiley, 2022) Rashwan, Rashwan A.; Nafea, A.; Jarad, Fahd; Hammad, Hasanen A.
This manuscript is devoted to obtaining a quadruple best proximity point for a cyclic contraction mapping in the setting of ordinary metric spaces. The validity of the theoretical results is also discussed in uniformly convex Banach spaces. Furthermore, some examples are given to strengthen our study. Also, under suitable conditions, some quadruple fixed point results are presented. Finally, as applications, the existence and uniqueness of a solution to a system of functional and integral equations are obtained to promote our paper.
Citation - WoS: 6
Citation - Scopus: 4
Symmetries of the Dual Metrics
(World Scientific Publ Co Pte Ltd, 2002) Baleanu, D
In this paper the symmetries of the dual manifold are investigated. We found the conditions when the manifold and its dual admit the same Killing vectors and Killing-Yano tensors. The dual conformal Killing vectors and dual conformal Killing-Yano tensors were investigated. In the case of an Einstein's metric g(munu) the corresponding equations for its dual were found. The examples of Kerr-Newman geometry and the separable coordinates in 1 + 1 dimensions axe analyzed in details.
Citation - WoS: 2
Citation - Scopus: 3
An Extension of the Clark-Ocone Formula Under Benchmark Measure for Levy Processes
(Taylor & Francis Ltd, 2012) Okur, Yeliz Yolcu
The classical Clark-Ocone theorem states that any random variable F is an element of D-1,2(W) subset of L-2 (F-T, P) can be represented as F = E[F] + integral(T)(0) E[DtF vertical bar F-t]dWd(t), where E[.vertical bar F-t] denotes the conditional expectation, W(.) is a Brownian motion with canonical filtration {Ft}(t is an element of[0,T]) and D denotes the Malliavin derivative in the direction of W. Since many applications in financial mathematics require representation of random variables with respect to risk neutral martingale measure, an equivalent martingale measure version of this theorem was stated by Karatzas and Ocone (Stoch. Stoch. Rep. 34 (1991), 187-220). In this paper, we extend these results to be valid for square integrable pure jump Levy processes with no drift and for square integrable Ito-Levy processes using Malliavin calculus and white noise analysis. This extension might be useful for some applications in finance. As an application of our result, we calculate explicitly the closest hedge strategy for the digital option whose pay-off, F = chi([H,K))(S(T)) is not an element of D-1,2(W,(N) over tilde), is square integrable and the stock price S(.) is driven by a Levy process.
Citation - WoS: 6
Citation - Scopus: 5
Fixed Points of Generalized Contraction Mappings in Cone Metric Spaces
(Univ Osijek, dept Mathematics, 2011) Turkoglu, Duran; Abdeljawad, Thabet; Abuloha, Muhib; Abdeljawad, Thabet; Matematik
In this paper, we proved a fixed point theorem and a common fixed point theorem in cone metric spaces for generalized contraction mappings where some of the main results of Ciric in [8, 27] are recovered.
Citation - WoS: 2
Special Issue on Advances in Fractional Dynamics in Mechanical Engineering
(Sage Publications Ltd, 2016) Lopes, Antonio Mendes; Hristov, Jordan Yankov; Cattani, Carlo; Baleanu, Dumitru; Mohyud-Din, Syed Tauseef; Yang, Xiao-Jun
Citation - WoS: 8
Citation - Scopus: 8
Dynamic Shear Force Amplification in Regular Frame-Wall Systems
(Wiley-blackwell, 2016) Kazaz, Ilker; Gulkan, Polat
A parametric study is conducted to investigate the dynamic shear amplification factor (DAF) in low-to-mid-rise frame-wall systems in which the reinforcement curtailment along the height matches the required code strength. The level of frame-wall interaction is varied by changing the wall index, defined as the ratio of the total wall area to the floor plan area, in a generic frame-wall system, and its correlation with the DAF is investigated. Wall index values ranging in the 0.2% to 2% interval are selected. Walls with lengths of 3m, 5m and 8m are used in the design of model buildings of 4, 8 and 12 stories. Shear-flexure beam continuum formulation is used in design and modeling. The global behavior is analyzed using nonlinear response history procedure using spectrum compatible ground motions. It is found that the primary source of amplification is the level of inelastic demand on the system. Walls designed for code-specified force reduction factor R=6 experienced an average base shear force amplification in the order of 1.64 with standard deviation of 0.19 with respect to design shear force. Amplification diminishes with decreasing R. An expression for the dynamic amplification factor as a function of the number of stories and force reduction factor R is proposed. Copyright (C) 2015 John Wiley & Sons, Ltd.
Citation - WoS: 27
Citation - Scopus: 29
Nonnormal Regression. I. Skew Distributions
(Taylor & Francis inc, 2001) Islam, MQ; Tiku, ML; Yildirim, F
In a linear regression model of the type y = thetaX + e, it is often assumed that the random error e is normally distributed. In numerous situations, e.g., when y measures life times or reaction times, e typically has a skew distribution. We consider two important families of skew distributions, (a) Weibull with support IR: (0, infinity) on the real line, and (b) generalised logistic with support IR: (-infinity, infinity). Since the maximum likelihood estimators are intractable in these situations, we derive modified likelihood estimators which have explicit algebraic forms and are, therefore, easy to compute. We show that these estimators are remarkably efficient, and robust. We develop hypothesis testing procedures and give a real life example.
Citation - WoS: 1
Citation - Scopus: 1
Recent Developments and Applications on Discrete Fractional Equations and Related Topics
(Hindawi Ltd, 2013) Alzabut, Jehad; Sun, Shurong; Abdeljawad, Thabet
Citation - WoS: 2
Citation - Scopus: 3
Control Structure Design With Constraints for a Slung Load Quadrotor System
(Sage Publications Ltd, 2024) Leblebicioglu, Kemal; Ergezer, Halit
We propose a control structure for a quadrotor carrying a slung load with swing-angle constraints. This quadrotor is supposed to pass through the waypoints at specified speeds. First, a cascaded PID autopilot is designed, which adaptively gives attention to position and speed requirements as a function of their errors. Its parameters are found from an optimization problem solved using the PSO algorithm. Second, this controller's performance is improved by adding the Complementary Controller employing an ANN. 5. Training data for the ANN is created by solving optimal control problems. The ANN is activated when the swing angle constraint is about to be violated. It is trained using optimal control values corresponding to the cases where the swing angle falls in a particular band about the upper swing angle constraint. Simulations are performed in a MATLAB environment. Finally, some of the simulation results are validated on a physical system.
Citation - WoS: 26
Citation - Scopus: 17
The First Integral Method for Wu-Zhang Nonlinear System With Time-Dependent Coefficients
(Editura Acad Romane, 2015) Baleanu, Dumitru; Baleanu, Dumitru; Kilic, Bulent; Inc, Mustafa; Matematik
The first integral method is used to construct traveling wave solutions of Wu-Zhang nonlinear dynamical system with time-dependent coefficients. We obtained different types of exact solutions by using two types of variable transformations. The method is an effective tool to construct the different types.of exact solutions of nonlinear partial differential equations having real world applications.
Citation - WoS: 34
Citation - Scopus: 43
Clinoptilolite/Pcl-peg-pcl Composite Scaffolds for Bone Tissue Engineering Applications
(Sage Publications Ltd, 2017) Pazarceviren, Engin; Erdemli, Ozge; Keskin, Dilek; Tezcaner, Aysen
The aim of this study was to prepare and characterize highly porous clinoptilolite/poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) composite scaffolds. Scaffolds with different clinoptilolite contents (10% and 20%) were fabricated with reproducible solvent-free powder compression/particulate leaching technique. The scaffolds had interconnective porosity in the range of 55-76%. Clinoptilolite/poly(epsilon-caprolactone)-poly(ethylene glycol)poly(epsilon-caprolactone) scaffolds showed negligible degradation within eight weeks and displayed less water uptake and higher bioactivity than poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) scaffolds. The presence of clinoptilolite improved the mechanical properties. Highest compressive strength (5.6 MPa) and modulus (114.84 MPa) were reached with scaffold group containing 20% clinoptilolite. In vitro protein adsorption capacity of the scaffolds was also higher for clinoptilolite/poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) scaffolds. These scaffolds had 0.95 mg protein/g scaffold adsorption capacity and also higher osteoinductivity in terms of enhanced ALP, OSP activities and intracellular calcium deposition. Stoichiometric apatite deposition (Ca/P = 1.686) was observed during cellular proliferation analysis with human fetal osteoblasts cells. Thus, it can be suggested that clinoptilolite/poly(epsilon-caprolactone)poly(ethylene glycol)-poly(epsilon-caprolactone) composite scaffolds could be promising carriers for enhancement of bone regeneration in bone tissue engineering applications.
Citation - WoS: 24
Citation - Scopus: 27
Partially Coherent Airy Beam and Its Propagation in Turbulent Media
(Springer Heidelberg, 2013) Sermutlu, Emre; Eyyuboglu, Halil T.
The properties of partially coherent Airy beam propagating in turbulent media are investigated. Firstly the variations in the intensity profile and the location of the Airy beam peak with respect to dislocation and width parameters are examined. On the source plane, it is shown that there is a threshold value of the dislocation parameter which determines whether the beam peak will lie on the negative or positive side of the axis. The changes in source beam power and source beam size with respect to dislocation and width parameters are also examined. Then analysis is made for partially coherent Airy beam propagating in turbulence against variations in propagation distance, dislocation and width parameters, structure constant and partial coherence. It is found that the peak of the Airy beam will always shift to the right for increasing propagation distance. But this shift will become less as the dislocation and width parameters are increased. Finally it is shown that higher levels of turbulence and partial coherence will lead to more spreading and shift the beam peak more toward the on-axis position.
Citation - WoS: 67
Citation - Scopus: 69
The Fractional Model of Spring Pendulum: New Features Within Different Kernels
(Editura Acad Romane, 2018) Baleanu, Dumitru; Baleanu, Dumitru; Asad, Jihad H.; Jajarmi, Amin; Matematik
In this work, new aspects of the fractional calculus (FC) are examined for a model of spring pendulum in fractional sense. First, we obtain the classical Lagrangian of the model, and as a result, we derive the classical Euler-Lagrange equations of the motion. Second, we generalize the classical Lagrangian to fractional case and derive the fractional Euler-Lagrange equations in terms of fractional derivatives with singular and nonsingular kernels, respectively. Finally, we provide the numerical solution of these equations within two fractional operators for some fractional orders and initial conditions. Numerical simulations verify that taking into account the recently features of the FC provides more realistic models demonstrating hidden aspects of the real-world phenomena.
Algebraic Integration of Sigma-Model Field Equations
(Springer, 2009) Yilmaz, N. T.
We prove that the dualization algebra of the sigma model with a symmetric coset space is a Lie algebra and show that it generates an appropriate adjoint representation that allows integrating the field equations locally, which yields first-order equations.
Citation - WoS: 12
Citation - Scopus: 14
Variational Principles in the Frame of Certain Generalized Fractional Derivatives
(Amer inst Mathematical Sciences-aims, 2020) Jarad, Fahd; Abdeljawad, Thabet
In this article, we study generalized fractional derivatives that contain kernels depending on a function on the space of absolute continuous functions. We generalize the Laplace transform in order to be applicable for the generalized fractional integrals and derivatives and apply this transform to solve some ordinary differential equations in the frame of the fractional derivatives under discussion.
Citation - WoS: 24
Citation - Scopus: 23
Scintillation Index of Flat-Topped Gaussian Laser Beam in Strongly Turbulent Medium
(Optical Soc Amer, 2011) Gercekcioglu, Hamza; Baykal, Yahya
In a strongly turbulent medium, the scintillation index of flat-topped Gaussian beams is derived and evaluated. In the formulation, unified solution of Rytov method is utilized. Our results correctly reduce to the existing strong turbulence scintillation index of the Gaussian beam, and naturally to spherical and plane wave scintillations. Another checkpoint of our result is the scintillation index of flat-topped Gaussian beams in weak turbulence. Regardless of the order of flatness, scintillations of flat-topped Gaussian beams in strong turbulence are found to be determined mainly by the small-scale effects. For large-sized beams in moderate and strongly turbulent medium, flatter beams exhibit smaller scintillations. (C) 2011 Optical Society of America
Enhancing Efficiency of an Old Hydropower Plant Turbine Through a Mutual Runner Design and Component Optimization
(Sage Publications Ltd, 2025) Seydim, Sila; Yildirim, Gozde; Ulucak, Oguzhan; Buyuksolak, Fevzi; Ejder, Beril; Kantar, Ece Nil; Celebioglu, Kutay
This paper presents a systematic approach to the rehabilitation process of Sar & imath;yar HEPP, a hydroelectric power plant that has been operational for more than 50 years. Units 1 and 2 (U1-U2) were originally designed with a head of 93 m and a turbine power of 48.5 MW, while Units 3 and 4 (U3-U4) were designed with a lower head of 76.5 m but the same turbine power of 48.5 MW. A methodology combining reverse engineering and CFD analysis is developed to identify and evaluate the critical parameters that have an impact on the existing turbine performance. A hybrid design is proposed to replace the existing two different types of turbines, which reduces manufacturing costs and design time. The performance of the new hybrid design is evaluated in detail with CFD analysis. For both existing and hybrid design, steady and unsteady analyses are performed. For all of the situations hill charts are obtained and the comparison of the old and new hybrid design is discussed in detail. The results show that the new design has improved the efficiency of the turbine and the power plant, resulting in a 14.2% efficiency increase in U1-U2 and a 21% system efficiency improvement in U3-U4. This study provides a guide to designers and practitioners for the rehabilitation of hydroelectric power plants.

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