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End date: 2009Publication Index: Scopus

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Now showing 1 - 10 of 606
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    Article
    Citation - WoS: 11
    Citation - Scopus: 14
    A Neural Network Model for the Assessment of Partners' Performance in Virtual Enterprises
    (Springer London Ltd, 2007) Sari, Burak; Amaitik, Saleh; Kilic, S. Engin
    In response to increasing international competition, enterprises have been investigating new ways of cooperating with each other to cope with today's unpredictable market behaviour. Advanced developments in information & communication technology (ICT) enabled reliable and fast cooperation to support real-time alliances. In this context, the virtual enterprise (VE) represents an appropriate cooperation alternative and competitive advantage for the enterprises. VE is a temporary network of independent companies or enterprises that can quickly bring together a set of core competencies to take advantage of market opportunity. In this emerging business model of VE, the key to enhancing the quality of decision making in the partner companies' performance evaluation function is to take advantage of the powerful computer-related concepts, tools and technique that have become available in the last few years. This paper attempts to introduce a neural network model, which is able to contribute to the extrapolation of the probable outcomes based on available pattern of events in a virtual enterprise. Quality, delivery and progress were selected as determinant factors effecting the performance assessment. Considering the features of partner performance assessment and neural network models, a back-propagation neural network that includes a two hidden layers was used to evaluate the partner performance.
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    Article
    Citation - WoS: 65
    Citation - Scopus: 67
    An Electrochromic and Fluorescent Polymer Based on 1-(1
    (Elsevier Science Sa, 2008) Cihaner, Atilla; Algi, Fatih
    A novel polymer was synthesized by electrochemical polymerization of 1-(1-naphthyl)-2,5-di-2-thienyl-1H-pyrrole (SNS-1-NAPH). The corresponding polymer (PSNS-1-NAPH) was characterized by cyclic voltammetry, FT-IR and UV-vis spectroscopy. The polymer has a very well-defined and reversible redox process in both organic and aqueous solutions. Furthermore, it shows stable electrochromic behavior; yellow in the neutral state, green in the intermediate state and violet in the oxidized state. PSNS-1-NAPH is soluble in common solvents. Although SNS-1-NAPH is almost nonfluorescent, its polymer is a yellow and/or green light emitter. (c) 2007 Elsevier B.V. All rights reserved.
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    Letter
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    Article
    Citation - WoS: 16
    Citation - Scopus: 16
    q-bernstein Polynomials of the Cauchy Kernel
    (Elsevier Science inc, 2008) Ostrovska, Sofiya
    Due to the fact that in the case q > 1, q-Bernstein polynomials are not positive linear operators on C[0, 1], the study of their approximation properties is essentially more difficult than that for 0 < q < 1. Despite the intensive research conducted in the area lately, the problem of describing the class of functions in C[0, 1] uniformly approximated by their q-Bernstein polynomials (q > 1) is still open. In this paper, the q-Bernstein polynomials B-n,B-q(f(a); z) of the Cauchy kernel f(a) = 1/(z - a), a is an element of C \ [0, 1] are found explicitly and their properties are investigated. In particular, it is proved that if q > 1, then polynomials B-n,B-q(f(a); z) converge to f(a) uniformly on any compact set K subset of {z : vertical bar z vertical bar < vertical bar a vertical bar}. This result is sharp in the following sense: on any set with an accumulation point in {z : vertical bar z vertical bar > vertical bar a vertical bar}, the sequence {B-n,B-q(f(a); z) is not even uniformly bounded. (C) 2007 Elsevier Inc. All rights reserved.
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    Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Rock mass response model for circular openings
    (Canadian Science Publishing, 2007) Sari, Dursun
    The main parameters affecting the failure and deformation state of the rock mass around a circular opening are the level of vertical and horizontal in situ stresses, the characteristics of the rock mass, the diameter of the opening, and the support pressure. The influence of all these parameters on the stress-induced final deformations around circular openings was investigated by a finite difference based two-dimensional numerical simulation for both hydrostatic and nonhydrostatic stress field conditions. From the results of the parametric studies, the variation of tunnel strain versus the ratio of uniaxial compressive strength of the rock mass to in situ vertical stress and the ratio of radial support pressure to in situ vertical stress for fair quality and poor quality rock masses was statistically analysed. As a result of the three-dimensional nonlinear regression analysis and surface curve fitting process by means of a large number of models, a best-fit model with the best correlation with these dimensionless parameters was proposed for calculating tunnel strains and ground response curves. Specific charts were created to highlight the influence of parameters on the deformation response of the openings to various support pressures.
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    Article
    Citation - WoS: 96
    Citation - Scopus: 100
    Effect of Progesterone on Dppc Membrane: Evidence for Lateral Phase Separation and Inverse Action in Lipid Dynamics
    (Elsevier Science inc, 2005) Korkmaz, F; Severcan, F
    Interactions of progesterone with zwitterionic dipalmitoyl phosphatidylcholine (DPPC) triultilamellar liposomes were investigated as a function of temperature and progesterone concentration by using three non-invasive techniques namely Fourier transform infrared spectroscopy, turbidity at 440 nm, and differential scanning calorimetry. The results reveal that progesterone changes the physical properties of DPPC bilayers by decreasing the main phase-transition temperature, abolishing the pre-transition, broadening the phase-transition profile, disordering the system both in gel and liquid crystalline phase, increasing the dynamics at low concentrations whereas stabilizing the membrane at high concentrations, and inducing phase separation. Progesterone does not change the hydration of the C=O groups, while it strengthens the hydrogen bonding between the PO (2) over bar groups of lipids and the water molecules around. (c) 2005 Elsevier Inc. All rights reserved.
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    Article
    Citation - WoS: 24
    Citation - Scopus: 27
    Global Asymptotic Stability of Cellular Neural Networks With Unequal Delays Lmi Approach
    (Iee-inst Elec Eng, 2004) Singh, V
    A criterion for the global asymptotic stability and uniqueness of the equilibrium point of cellular neural networks with unequal delays is presented. The criterion is computationally efficient, since it is in the form of linear matrix inequality (LMI).
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    Conference Object
    Citation - Scopus: 3
    Error Density Metrics for Business Process Model
    (2009) Tonbul,G.; Misra,S.
    In this paper, metrics for business process model (BPM), are proposed, which are capable to measure the usability and effectiveness of BPMs. The proposed model is adapting error density metrics to BPMs by considering the similarities between the conceptual characteristics of BPMs and software products. We applied seven software metrics for evaluating quality of business processes/process models. Results show that our metrics help the organization to improve their process, as weighted measurements are indicators for unexpected situations/behaviour for business processes. © 2009 IEEE.
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    Article
    Citation - WoS: 64
    Citation - Scopus: 69
    A Semi-Empirical Approach for Residual Stresses in Electric Discharge Machining (edm)
    (Elsevier Sci Ltd, 2006) Ekmekci, Bulent; Tekkaya, A. Erman; Erden, Abdulkadir
    High residual stresses are developed on the surfaces of electric discharge machined parts. In this study, layer removal method is used to measure the residual stress profile as a function of depth beneath the surface caused by die sinking type EDM. Cracking and its consequences on residual stresses are also studied on samples machined at long pulse durations. A modified empirical equation is developed for scaling residual stresses in machined surfaces with respect to operating conditions. In this model, a unit amplitude shape function representing change in curvature with respect to removal depth is proposed. The proposed form is found to be a special form of a Gauss Distribution. It is the sum of two Gaussian peaks, with the same amplitude and pulse width but opposite center location. The form can be represented by three constant coefficients. These coefficients depend on the released energy by a power function. (C) 2005 Elsevier Ltd. All rights reserved.
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    Conference Object
    A Linear Time Algorithm for the Prediction of Compression During Multimedia Transmission
    (2009) Çevik,A.
    In this paper, alternative approaches and solutions are introduced to improve the quality of multimedia transmissions on various services. Regarding the improvement, several approaches are proposed incluing an automated network feedback approach based on a two-way language protocol. Secondly, and independent from automated feedback, measure-once and linear-time measure-many tracking algorithms are proposed in order to make an approximation about the quality/compression ratio of the transmission of a multimedia object.