Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/260
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Article Citation - WoS: 1Citation - Scopus: 1Determination of Chemisorption Probabilities of Hydrogen Molecules on a Nickel Surface by Artificial Neural Network(Croatian Chemical Soc, 2008) Güvenç, Ziya Burhanettin; Boeyuekata, Mustafa; Kocyigit, Yuecel; Guevenc, Ziya B.; Böyükata, Mustafa; Bilgisayar MühendisliğiDissociative chemisorption probabilities for H-2(v, j) + Ni(100) collision systems have been estimated by using Artificial Neural Network (ANN). For training, previously determined probability values via molecular dynamics simulations have been used. Performance of the ANN, for predicting any quantities in the molecule-surface interaction, has been investigated. Effects of the surface sites and the rovibrational states of the molecule on the process are analyzed. The results are in good agreement with the related previous studies.Article Siber Güvenlik Yatırım Kararları Üzerine Literatür İncelemesi(2016) Şentürk, Hakan; Çil, Celal Zaim; Sagıroglu, SerefKarmaşıklığı ve sıklığı her geçen gün artan siber saldırıların yol açtığı yüksek ekonomik zararlar ile bu saldırılara karşı korumasağlayan çok sayıda siber güvenlik teknolojisi ürünlerinin yatırım alternatifi olarak sunulduğu güvenlik sektörü, alanda yapılançalışmaların odak noktasını siber güvenliğin ekonomik boyutuna yöneltmiştir. Kısıtlı kaynak şartları altında siber güvenlikyatırım kararlarının verilebilmesine yönelik kullanılabilecek yöntemlerin belirlenmesi ihtiyacı öne çıkmıştır.Bu çalışmada siber güvenlik yatırım kararlarının verilmesi sürecinde uygulanabilecek yatırım stratejileri, siber güvenlikrisklerinin belirlenmesi ve ölçülmesi, güvenlik saldırılarının maliyet ve etkisinin ölçülmesi, güvenlik teknolojilerinin etkinliğininölçülmesi ve güvenlik yatırımlarının en uygun seviyesinin belirlenmesi olmak üzere beş kategoride alanda son onbeş yıldayapılan akademik çalışmalar incelenmiş, literatürdeki boşluklar ortaya konularak sonraki araştırmalara yön verilmesiamaçlanmıştır.Article Citation - WoS: 18Citation - Scopus: 19Scattering by an Impedance Half-Plane: Comparison of the Solutions of Raman/Krishnan and Maliuzhinets/Senior(Electromagnetics Acad, 2009) Umul, Y. Z.There are three approaches for the solution of the diffraction problem of plane waves by an impedance half-plane in the literature. The diffracted field expressions, obtained by the related methods, are compared numerically. The examination of the scattered field shows that the most reliable solution is the field representation of Raman and Krishnan. Since the diffracted fields of Senior and Maliuzhinets do not compensate the discontinuities of the geometrical optics waves at the transition regions.Article Citation - WoS: 3Citation - Scopus: 4Po and Ptd Approach To the Diffraction Problem by a Resistive Half-Plane(Taylor & Francis Ltd, 2014) Basdemir, Husnu DenizDiffracted fields from a resistive half-plane were investigated by the method of physical optics (PO) and the physical theory of diffraction. The coefficient of the PO scattering integral was derived for the first time for the resistive half-plane. Uniform fringe field expressions were obtained in terms of the Fresnel functions. The resultant expressions of the fringe fields were plotted and analyzed numerically.Article Citation - WoS: 4Citation - Scopus: 4Electric Charges That Behave as Magnetic Monopoles(E M W Publishing, 2010) Umul, Y. Z.The memristor theory of Chua [1] provides a connection with the charge and magnetic flux in an electric circuit. We define a similar relation for the electric and magnetic flux densities in electromagnetism. Such an attempt puts forward interesting results. For example, the magnetic charges do not exist in nature however the electric charges behave as the magnetic monopoles in special media. We support our theory with the results of the recent experiments on materials named as spin ice.Editorial Citation - WoS: 3Citation - Scopus: 2Reply To the "comments on 'fringe Waves in an Impedance Half-Plane(E M W Publishing, 2014) Basdemir, Husnu DenizArticle Citation - WoS: 1Literature Review on Cyber Security Investment Decisions(Gazi Univ, 2016) Cil, Celal Zaim; Sagiroglu, Seref; Senturk, HakanSevere financial losses incurred by cyber security attacks with increasing complexity and frequency, as well as booming cyber security sector offering variety of products as investment options have led the focus of the research in the field to the economic dimension of cyber security. The need for determination of methods to be used when making cyber security investment decisions under budget constraints have become prominent. In five sections as the cyber security investment strategies, risk identification and measurement, attack costs and impacts calculation, measurement of technology effectiveness and determination of optimum level of cyber security investments, this study reviews and evaluates the academic literature on economic aspects of cyber security for the last fifteen years and aims to provide research directions by pinpointing literature gaps.Article Citation - WoS: 15Citation - Scopus: 16Scintillation Behaviour of Vortex Beams in Strong Turbulence Region(Taylor & Francis Ltd, 2016) Eyyuboglu, H. T.We study the scintillation behaviour of vectorial vortex beams in strong turbulence region. For this purpose, a list of vortex source beams is prepared. Then their scintillation performances are analysed one by one using the random phase screen approach. The results indicate that there will always be scintillation reductions with increasing values of topological charge, although its effect will diminish as we go towards higher values of the topological charge. The increases in the other specific beam parameters seem to have opposite effect. For the vectorial Hermite Gaussian beam, the use of higher orders will also aid scintillation reductions. It is foreseen that the outcome of this study will be useful for long haul optical communication links.Correction Citation - WoS: 15Citation - Scopus: 21Higher Order Annular Gaussian Laser Beam Propagation in Free Space (Vol 45, Art No 038002, 2006)(Spie-int Society Optical Engineering, 2006) Eyyuboglu, HT; Yenice, YE; Baykal, YPropagation of higher order annular Gaussian (HOAG) laser beams in free space is examined. HOAG beams are defined as the difference of two Hermite-Gaussian (HG) beams; thus, they can be produced by subtracting a smaller beam from a larger beam, that are co-centered and both possess HG mode field distributions. Such beams can be considered as a generalization of the well-known annular Gaussian beams. We formulate the source and receiver plane characteristics and kurtosis parameter of HOAG beams propagating in free space and evaluate them numerically. In comparison to HG beams, HOAG beams have a broader beam size with outer lobes of kidney shape. The amount of received power within the same receiver aperture size, that is, power in bucket, is generally lower for higher order beams. The convergence of the kurtosis parameter to an asymptotic value for higher order beams takes much longer propagation distances compared to zero-order beams. (c) 2006 Society of Photo-Optical Instrumentation Engineers.Article Citation - WoS: 13Citation - Scopus: 13Angle-Of Fluctuations for General-Type Beams(Spie-soc Photo-optical instrumentation Engineers, 2007) Eyyuboglu, Halil T.; Baykal, YahyaStarting with the recently introduced phase correlation function of a general-type beam, the angle-of-arrival fluctuations are derived and evaluated in atmospheric turbulence for lowest-order Gaussian, cos-Gaussian, cosh-Gaussian, annular, and flat-topped beams. Our motivation is to examine the improvement in the performance of optical atmospheric links when such beams are employed. For these beams, the dependence of the angle-of-arrival fluctuations on the propagation length, displacement and focusing parameters, source size, inner and outer scales of turbulence, and receiver radius is investigated. It is found that in the majority of the cases examined, the angle- of- arrival fluctuations remain small and hence are not expected to adversely affect the operation of free-space atmospheric links. It is observed that amongst the beams considered, the cos-Gaussian beam offers the least amount of angle-of-arrival fluctuations, while the worst behavior is exhibited by the cosh-Gaussian beam. This situation is reversed, however, if focused beams are used. (C) 2007 Society of Photo-Optical Instrumentation Engineers.