Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/260
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Editorial Citation - WoS: 5Citation - Scopus: 5Comments on "on the Modified Theory of Physical Optics(Ieee-inst Electrical Electronics Engineers inc, 2014) Umul, Yusuf Z.Article Citation - WoS: 8Citation - Scopus: 10Spectrum-Aware and Energy-Adaptive Reliable Transport for Internet of Sensing Things(Ieee-inst Electrical Electronics Engineers inc, 2018) Bicen, A. Ozan; Ergul, Ozgur; Akan, Ozgur B.; Ozan Bicen, A.Wireless sensors equipped with cognitive radio, i.e., cognitive radio sensor networks (CRSN), can access the spectrum in an opportunistic manner and coexist with licensed users to mitigate the crowded spectrum problem and provide ubiquitous remote event monitoring and tracking for cyber-physical systems. In this paper, a novel transport layer protocol for CRSN, spectrum-aware energy-adaptive reliable transport protocol is presented to enable energy-adaptive collaborative event sensing in spectrum-scarce cyber-physical systems. To the best of our knowledge, this is the first attempt to specifically devise a reliable event transport scheme for CRSN.Article Citation - WoS: 10Citation - Scopus: 10Scattering of Evanescent Plane Waves by a Black Wedge at the Interface Between Isorefractive Media(Ieee-inst Electrical Electronics Engineers inc, 2016) Basdemir, Husnu DenizThe scattering of evanescent plane waves by a black wedge located at the interface of two isorefractive media is investigated in order to extend the results for the perfectly conducting half-plane case reported by Uslenghi (2013). The geometrical optics, in addition to the diffracted and scattered fields, are analyzed numerically. The effect of the isorefractive media on the diffracted field and the effect of the evanescent plane-wave excitation on the scattered field are also examined.Article Citation - WoS: 12Citation - Scopus: 12Scattering of Waves by a Perfectly Conducting Wedge Residing at the Interface Between Two Isorefractive Media(Ieee-inst Electrical Electronics Engineers inc, 2016) Basdemir, Husnu DenizScattered field by a wedge that is surrounded by isorefractive media is analyzed. A series-based method is introduced and applied to the wedge problem with soft boundary condition. The fields are examined numerically. The numerical results show that the proposed method is suitable for analysis of these kinds of problems.Article Citation - WoS: 72Citation - Scopus: 85Entropy-Functional Online Adaptive Decision Fusion Framework With Application To Wildfire Detection in Video(Ieee-inst Electrical Electronics Engineers inc, 2012) Toreyin, Behcet Ugur; Kose, Kivanc; Cetin, A. Enis; Gunay, OsmanIn this paper, an entropy-functional-based online adaptive decision fusion (EADF) framework is developed for image analysis and computer vision applications. In this framework, it is assumed that the compound algorithm consists of several subalgorithms, each of which yields its own decision as a real number centered around zero, representing the confidence level of that particular subalgorithm. Decision values are linearly combined with weights that are updated online according to an active fusion method based on performing entropic projections onto convex sets describing subalgorithms. It is assumed that there is an oracle, who is usually a human operator, providing feedback to the decision fusion method. A video-based wildfire detection system was developed to evaluate the performance of the decision fusion algorithm. In this case, image data arrive sequentially, and the oracle is the security guard of the forest lookout tower, verifying the decision of the combined algorithm. The simulation results are presented.Article Citation - WoS: 12Citation - Scopus: 13An Online Adaptive Cooperation Scheme for Spectrum Sensing Based on a Second-Order Statistical Method(Ieee-inst Electrical Electronics Engineers inc, 2012) Toreyin, Behcet Ugur; Qaraqe, Khalid A.; Cetin, A. Enis; Yarkan, SerhanSpectrum sensing is one of the most important features of cognitive radio (CR) systems. Although spectrum sensing can be performed by a single CR, it is shown in the literature that cooperative techniques, including multiple CRs/sensors, improve the performance and reliability of spectrum sensing. Existing cooperation techniques usually assume a static communication scenario between the unknown source and sensors along with a fixed propagation environment class. In this paper, an online adaptive cooperation scheme is proposed for spectrum sensing to maintain the level of sensing reliability and performance under changing channel and environmental conditions. Each cooperating sensor analyzes second-order statistics of the received signal, which undergoes both correlated fast and slow fading. Autocorrelation estimation data from sensors are fused together by an adaptive weighted linear combination at the fusion center. Weight update operation is performed online through the use of orthogonal projection onto convex sets. Numerical results show that the performance of the proposed scheme is maintained for dynamically changing characteristics of the channel between an unknown source and sensors, even under different physical propagation environments. In addition, it is shown that the proposed cooperative scheme, which is based on second-order detectors, yields better results compared with the same fusion mechanism that is based on conventional energy detectors.Article Citation - WoS: 9Citation - Scopus: 9Physical Optics Scattering of Waves by a Half-Plane With Different Face Impedances(Ieee-inst Electrical Electronics Engineers inc, 2011) Umul, Y. Z.The theory of physical optics is extended for the diffraction problem of waves by a half-plane with different face impedances. The kernel of the modified theory of physical optics integral is expressed in terms of the Maliuzhinets function. The resultant integral is evaluated asymptotically for large values of the wavenumber. The results are examined numerically.Article Citation - WoS: 52Citation - Scopus: 55Modified Theory of Physical Optics Solution of Impedance Half Plane Problem(Ieee-inst Electrical Electronics Engineers inc, 2006) Umul, Yusuf Z.The scattering of electric polarized plane waves from an impedance half plane problem is examined by the method of modified theory of physical optics (MTPO). Two integrals, consisting of incident and reflected scattered fields, are obtained. These integrals are evaluated asymptotically by the methods of stationary phase and edge point. The obtained scattered fields are compared with the exact solution numerically.