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Article A Practical Distributed Lightweight Multi-Hop Time Synchronization Algorithm for Linear Wireless Sensor Networks Implemented on a Pic Based System With Realistic Experimental Analysis(Sakarya University, 2020) Erpay, A.; Al Imran, M.A.; Kara, A.Time synchronization is fundamental in the distributed networked systems, especially in Wireless Sensor Networks where a global time is essential to make sense of the events like collection of data and scheduled sleep/wake-up of nodes. There exists numerous time synchronization algorithms and techniques in the literature. Nonetheless, these proposed methods lack realistic experimentation of the synchronization process which is vital from the realization point of view. This study aims to bridge that gap by presenting a distributed lightweight time synchronization protocol implemented on an inexpensive PIC platform. Furthermore, PIC-based systems hadn’t been investigated before and gives an idea of the simplicity of the algorithm. Experimental analysis was done to see the performance of the protocol. The core motivation of the experiments was to the study the impact of the environment (e.g. indoor, outdoors, temperature variations and interference) on the synchronization. Our findings show that temperature indeed impedes the synchronization accuracy. © 2020, Sakarya University. All rights reserved.Article Citation - WoS: 23Citation - Scopus: 27Comparison of Improved Slope Uniform Theory of Diffraction With Some Geometrical Optic and Physical Optic Methods for Multiple Building Diffractions(Taylor & Francis inc, 2009) Tabakcioglu, M. B.; Kara, A.This article presents a review of diffraction algorithms based on the uniform theory of diffraction for multiple building transition zone diffractions and proposes an improved uniform theory of diffraction model for fast and more accurate field prediction for multiple diffractions. The proposed method is based on the improved version of the slope uniform theory of diffraction and Fresnel zone concept, called the slope uniform theory of diffraction with convex hull. This article also provides a comparison for uniform theory of diffraction based algorithms and discusses the results for computation time and accuracy. Furthermore, the slope uniform theory of diffraction and the slope uniform theory of diffraction with convex hull methods are compared with a physical optics solution based on numerical computation of the Kirchhoff-Huygens integrals. Results of extensive simulations are presented and discussed for the development of fast and accurate radio network planning tools.
