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Conference Object Citation - WoS: 17Citation - Scopus: 23Maintenance, Sustainability and Extendibility in Virtual and Remote Laboratories(Elsevier Science Bv, 2011) Kara, Ali; Ozbek, Mehmet Efe; Cagiltay, Nergiz Ercil; Aydin, ElifThis study presents discussions on sustainability of Virtual and Remote Laboratories (VRL), and provides challenges toward maintenance of VRLs. Technical and pedagogical issues in extension and sustenance of VRLs are discussed with the experiences of the authors gained in the development of a VRL system, European Remote Radio Laboratory (ERRL) platform. Moreover, the study presents actions to be taken in sustenance plan and expendability of VRL system with the advances in Information and Communication Technologies (ICT) and educational technologies along with the needs of educators and learners in formal education. (C) 2011 Published by Elsevier Ltd.Conference Object Study of an Rfid Based Moving Object Tracking System(Istanbul Technical Univ, 2007) Aydin, Elif; Oektem, Rusen; Dincer, Zeynep; Akbulut, I. KaanThis paper presents a study on localization and tracking of an object carrying an active RFID tag. The study incorporates processing of the signals received from transmitters.. in a way to locate and track the coordinate in an indoor environment. During the course of the project,, both outdoor and indoor experiments have been conducted. Empirical distance vs signal strength formulations are formed by use of the collected data. Deviation of the reported values from the theory is analyzed, and the effects of reflections from doors. windows, etc. are observed. In order to improve the accuracy of tracking, Bayesian and Kalman Filtering approaches are incorporated.Conference Object Citation - WoS: 4Dual-Frequency, Two Shorting Pin-Loaded Equilateral Triangular Patch Antennas(Electromagnetics Acad, 2012) Can, Sultan; Kapusuz, K. Yavuz; Aydin, ElifThis study presents the resonant frequencies of several antennas, which are dual-frequency antennas. These antennas possess two shorting pins to form dual frequency. Among several methods to provide dual operation, two shorting pins are used to form dual frequency equilateral triangular antennas since there are limited studies on this issue and higher frequency ratios are achievable. The present study has been done with this in mind in order to contribute to related literature on such antennas. Here, the parameters that affect the resonant frequencies of the antenna are also evaluated. The thickness, side length, and shorting pin positions are changed numerous times, and the resonant frequencies are examined according to the change of these parameters. Finally, the frequency ratios are determined for each variation, and the results are compared. The proposed antennas in present study achieved a frequency ratio around 5.7, which is significantly higher from the ones presented in the literature.Article ISAR Imaging of Drone Swarms at 77 GHz(Tubitak Scientific & Technological Research Council Turkey, 2025) Coruk, Remziye Busra; Kara, Ali; Aydin, ElifThe proliferation of easily available, internet-purchased drones, coupled with the emergence of coordinated drone swarms, poses a significant security threat for airspace. Detecting these swarms is crucial to prevent potential accidents, criminal misuse, and airspace disruptions. This paper proposes a novel inverse synthetic aperture radar (ISAR) imaging technique for high-resolution reconstruction of drone swarms at 77 GHz millimeter wave (mmWave) frequency, offering a valuable tool for military and defense antidrone systems. The key parameters affecting down-range and cross-range resolution (0.05 m), ultimately enabling the generation of detailed ISAR images are discussed. Here, we create diverse scenarios encompassing various swarm formations, sizes, and payload configurations by employing ANSYS simulations. To enhance image quality, different window functions are evaluated, and the Hamming window is selected due to its highest peak signal-to-noise ratio (PSNR) (16.3645) and structural similarity (SSIM) (0.9067) values, ensuring superior noise reduction and structural preservation. The results demonstrate that the effectiveness of high-resolution ISAR imaging in accurately detecting and characterizing drone swarms pave the way for enhanced airspace security measures.Conference Object Citation - WoS: 2Citation - Scopus: 3Design Considerations for Sub-Ghz Multilayer Microstrip Antenna for Near Ground Communication Links in Rural Areas(Ieee, 2017) Bilgin, Gulsima; Yilmaz, Vadi Su; Aydin, Elif; Kara, Ali; Department of Electrical & Electronics Engineering; Electrical-Electronics EngineeringThis paper presents some preliminary results of design and development of sub-GHz multilayer microstip antenna for use in near ground communication applications. In design stage of the antenna, iterative approach was applied. Firstly, a two layer microstrip antenna design process is presented. Next, the corners of the patch were cut, and a vertical wall on all sides of the antenna were introduced. In this way, both the size and resonant freqeuncy can be tuned. Moreover, as an application specific requirement, it is intended to embed this antenna into a metal box in order to protect it from man-made and natural environmental effects. This was also studied, and effects of the embedding ground on the antenna characteristics were examined. It is shown that the designed antenna provides -27dB resturn loss, and 7.3dB peak gain at 915MHz with the dimension of 150x200x13mm. Some preliminary measurements have proven the simulations.Article Citation - WoS: 6Citation - Scopus: 9Comparative Assessment of Electromagnetic Simulation Tools for Use in Microstrip Antenna Design: Experimental Demonstrations(Wiley, 2019) Bilgin, Gulsima; Yilmaz, Vadi Su; Kara, Ali; Aydin, ElifThis paper presents a better understanding of the use of finite integration techniques (FIT) and finite element method (FEM) in different types of microstrip antennas in order to determine which numerical method gives relatively more accurate results. Although the theoretical formulation based on Maxwell's equations of both FEM and FIT are approached from different aspects in the literature, there is still a lack of comparison of the same antenna type using different numerical methods employing FEM and FIT. Therefore, in this study, FEM and FIT were applied to two different types of microstrip antennas, and their simulation and experimental results was compared. For the first antenna demonstration, a multilayer structure was chosen to achieve one of the significant parameters. Then, a microstrip antenna with a compact structure was used in the second demonstration. Using these two antennas, the accuracy of FEM and FIT in different structures were compared and all simulated return loss and gain results were verified by the measured results. The experimental demonstrations show that FEM performs better for both types of microstrip antennas while FIT provides an adequate result for two-layer microstrip antennas.Article Citation - WoS: 8Citation - Scopus: 8A New Rf and Microwave Engineering Course Enriched With Advanced Technologies(Wiley, 2012) Aydin, Elif; Cagiltay, NergizIn this study, a curriculum model including recent developments and technologies in the Radio Frequency (RF) and Microwave Engineering field by using a blended approach is proposed. This study covers the description of the content of theoretical and hands on applications, the integration model of the technological tools into the proposed curriculum, and the instructional approaches used in the new course design. The main goal of the course is to prepare students for future professional careers in RF and Microwave Engineering by supporting them with new instructional technologies. The secondary goal of the course is to better prepare the students for the sequence of senior courses in the Electrical and Electronics Engineering program of Atilim University. The course is structured with a balance between theory and laboratory, including remote and in lab measurement experiments as well as modeling and designing microwave components by means of computer tools and design fabrication. The newly designed course is implemented at the Atilim University. The study also reports the first semester implementation. (C) 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 634645, 2012Article Citation - WoS: 17Citation - Scopus: 22Seven Principles of Instructional Content Design for a Remote Laboratory: a Case Study on Errl(Ieee-inst Electrical Electronics Engineers inc, 2011) Cagiltay, Nergiz Ercil; Aydin, Elif; Aydin, Cansu Cigdem; Kara, Ali; Alexandru, MarianThis paper discusses the results of a study of the requirements for developing a remote radio frequency (RF) laboratory for electrical engineering students. It investigates students' preferred usage of the technical content of a state-of-the-art RF laboratory. The results of this study are compared to previous findings, which dealt with other user groups (technicians in technical colleges and engineers in the RF domain). Based on the results of these analyses, seven essential principles for designing and developing such a laboratory were identified. As a case study, these principles were then implemented into a remote laboratory system. In this paper, the implementation examples are also provided and discussed. The primary aim of this study is to guide remote laboratory platform developers toward the most effective instructional design. This study also determined, from the remote laboratory system case study, what the requirements are of such a laboratory from the students' perspective.Conference Object Citation - WoS: 1Design and Analysis of Rectangular Dielectric Rod Antennas(Ieee, 2015) Demir, Mahmut; Ozkok, M. Aybars; Caliskan, Fatma; Aydin, ElifIn this study, rectangular dielectric rod antennas with different dimensions and different shapes are designed and analyzed using HFSS simulation software. To analyze the effects of these changes, five different antennas are designed and antenna gains and return loss values are compared.Article A New Model for Indoor Propagation Prediction Using Genetic Algorithm(Ieice-inst Electronics information Communications Eng, 2008) Aydin, ElifIn this study, a new, simple and accurate computation of the received signal strength (RSS) level for indoor environment is performed. The genetic algorithm (GA) approach is used for prediction of the RSS. The proposed model is formed on the knowledge of measurements without requiring any detail of the environment. The model provides a time efficient method to estimate RSS dynamically at any location in the test environment. The accuracy of the measurement results and the genetic algorithm approach are presented for three distinct transmitters located at different positions.
