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Now showing 1 - 10 of 227
  • Article
    Citation - WoS: 68
    Citation - Scopus: 82
    The Effect of Uncertainty on Learning in Game-Like Environments
    (Pergamon-elsevier Science Ltd, 2013) Ozcelik, Erol; Cagiltay, Nergiz Ercil; Ozcelik, Nese Sahin
    Considering the role of games for educational purposes, there has an increase in interest among educators in applying strategies used in popular games to create more engaging learning environments. Learning is more fun and appealing in digital educational games and, as a result, it may become more effective. However, few research studies have been conducted to establish principles based on empirical research for designing engaging and entertaining games so as to improve learning. One of the essential characteristics of games that has been unexplored in the literature is the concept of uncertainty. This study examines the effect of uncertainty on learning outcomes. In order to better understand this effect on learning, a game-like learning tool was developed to teach a database concept in higher education programs of software engineering. The tool is designed in two versions: one including uncertainty and the other including no uncertainty. The experimental results of this study reveal that uncertainty enhances learning. Uncertainty is found to be positively associated with motivation. As motivation increases, participants tend to spend more time on answering the questions and to have higher accuracy in these questions. (C) 2013 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 44
    Citation - Scopus: 45
    A Novel Electrochromic and Fluorescent Polythienylpyrrole Bearing 1,1′-Bipyrrole
    (Pergamon-elsevier Science Ltd, 2009) Cihaner, Atilla; Mert, Olcay; Demir, Ayhan S.
    A novel conducting polymer was successfully synthesized via electropolymerization of 1-(1H-pyrrol-1-yl)-2,5-di(thiophen-2-yl)-1H-pyrrole. The electrochemical and electro-optical properties of the corresponding polymer, which was the first example of polymer containing 1,1'-bipyrrole units, were elaborated using electroanalytical and spectroscopic techniques. Cyclic voltammograms and electro-optical studies showed that the polymer has a stable and well-defined reversible redox process as well as electrochromic behavior. The processable polymer film also possessed a yellowish orange light emitter property. (C) 2008 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 82
    Citation - Scopus: 87
    On Common Fixed Points in g-metric Spaces Using (e.a) Property
    (Pergamon-elsevier Science Ltd, 2012) Mustafa, Zead; Aydi, Hassen; Karapinar, Erdal
    In this paper, we introduce some new types of pairs of mappings (f, g) on G-metric spaces called G-weakly commuting of type G(f) and G-R-weakly commuting of type G(f). We obtain also several common fixed point results by using the (E.A) property. (c) 2012 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 178
    Citation - Scopus: 184
    Couple fixed point theorems for nonlinear contractions in cone metric spaces
    (Pergamon-elsevier Science Ltd, 2010) Karapinar, Erdal
    The notion of coupled fixed point is introduced by Bhaskar and Lakshmikantham (2006) in [13]. In this manuscript, some results of Lakshmikantham and Ciric (2009) in [5] are extended to the class of cone metric spaces. (C) 2010 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 94
    Citation - Scopus: 95
    A New Conducting Polymer Bearing 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (bodipy) Subunit: Synthesis and Characterization
    (Pergamon-elsevier Science Ltd, 2008) Cihaner, Atilla; Algi, Fatih
    A new monomer system based on thiophene, pyrrole and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene dye (SNS-BODIPY) was synthesized and its corresponding polymer (PSNS-BODIPY) was obtained via repetitive cycling or constant potential electrolysis in 0.1 M tetrabutylammonium hexafluorophosphate dissolved in dichloromethane. The PSNS-BODIPY film has very stable and well-defined reversible redox couples during p-doping process. Multi-electrochromic polymer film has a band gap of 2.9 eV with two absorption bands in its neutral state at 351 and 525 nm, attributed to the polymer backbone and BODIPY subunits, respectively. The percentage transmittance changes between both states (neutral and oxidized) were found as 12.1% for 351 nm and 17.7% for 525 nm in the visible region as well as 46.2% for 1050 nm in the near-infrared region. Beyond the robustness, the PSNS-BODIPY film has high redox stability (retaining 53.3% of its electroactivity at 351 nm after 2000 switching) with a low response time of 1.0 s. (C) 2008 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 25
    Citation - Scopus: 31
    Modified Criterion for Global Asymptotic Stability of Fixed-Point State-Space Digital Filters Using Two's Complement Arithmetic
    (Pergamon-elsevier Science Ltd, 2010) Singh, Vimal
    A criterion for the global asymptotic stability of fixed-point state-space digital filters using two's complement arithmetic is presented. The criterion is a modified form of a well-known criterion due to Mills, Mullis, and Roberts. The criterion is in the form of linear matrix inequality and, hence, computationally tractable. An example shows the effectiveness of the modified criterion. (C) 2009 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 40
    Citation - Scopus: 52
    Variable Structure Control of a Class of Uncertain Systems
    (Pergamon-elsevier Science Ltd, 2004) Efe, MÖ; Ünsal, C; Kaynak, O; Yu, XH
    This brief paper proposes a method for tuning the parameters of a variable structure controller. The approach presented extracts the error at the output of the controller and applies a nonlinear tuning law using this error measure. The adaptation mechanism drives the state tracking error vector to the sliding hypersurface and maintains the sliding mode. In the simulations, the approach presented has been tested on the control of Dulling oscillator and the analytical claims have been justified under the existence of measurement noise, uncertainty and large nonzero initial errors. (C) 2003 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 60
    Citation - Scopus: 64
    Computing Optimal Replacement Time and Mean Residual Life in Reliability Shock Models
    (Pergamon-elsevier Science Ltd, 2017) Eryilmaz, Serkan
    In this paper, matrix-based methods are presented to compute the optimal replacement time and mean residual lifetime of a system under particular class of reliability shock models. The times between successive shocks are assumed to have a common continuous phase-type distribution. The system's lifetime is represented as a compound random variable and some properties of phase-type distributions are utilized. Extreme shock model, run shock model, and generalized extreme shock model are shown to be the members of this class. Graphical illustrations and numerical examples are presented for the run shock model when the interarrival times between shocks follow Erlang distribution. (C) 2016 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 26
    An Empirical Analysis of Household Education Expenditures in Turkey
    (Pergamon-elsevier Science Ltd, 2016) Acar, Elif Oznur; Gunalp, Burak; Cilasun, Seyit Mumin
    Using Turkish Household Budget Surveys from 2003, 2007 and 2012, this paper investigates the determinants of household education expenditures within an Engel curve framework. In particular, we estimate Tobit regressions of real educational expenditures by income groups using a number of household characteristics (i.e. rural residence, employment status, age, educational attainment of the household head, household size, share of female students and primary school students in the household, and total number of students in the household) to examine if and to what extent the determinants of educational expenditures differ by income groups; income elasticities of educational spending evolves over time; and children from middle-class and poor families can benefit enough from educational opportunities. The estimated expenditure elasticities have lower values for the top- and the bottom income quartiles while they have larger values for the middle-income quartiles. The results also show that for all income groups the expenditure elasticity of education increases over time, indicating that Turkish households allocates greater share of their budgets to education expenditures. (C) 2016 Elsevier Ltd. All rights reserved.
  • Editorial
    Preface To the Special Issue on "17th International Conference on Emerging Nuclear Energy Systems (icenes'2015), 4-8 October 2015, Istanbul, Turkey"
    (Pergamon-elsevier Science Ltd, 2016) Sahin, Sumer; Sahin, Haci Mehmet; Martinez-Val, Jose; Wu, Yican
    [No Abstract Available]