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Citation - WoS: 17
Citation - Scopus: 23
Maintenance, Sustainability and Extendibility in Virtual and Remote Laboratories
(Elsevier Science Bv, 2011) Kara, Ali; Ozbek, Mehmet Efe; Cagiltay, Nergiz Ercil; Aydin, Elif
This 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.
Study of an Rfid Based Moving Object Tracking System
(Istanbul Technical Univ, 2007) Aydin, Elif; Oektem, Rusen; Dincer, Zeynep; Akbulut, I. Kaan
This 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.
Citation - WoS: 8
Citation - Scopus: 8
A New Rf and Microwave Engineering Course Enriched With Advanced Technologies
(Wiley, 2012) Aydin, Elif; Cagiltay, Nergiz
In 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, 2012
Citation - WoS: 17
Citation - Scopus: 22
Seven 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, Marian
This 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.
Citation - WoS: 1
Citation - Scopus: 3
Calculation of Resonant Frequencies of a Shorting Pin-Loaded Etma With Ann
(Wiley-blackwell, 2014) Can, Sultan; Kapusuz, Kamil Yavuz; Aydin, Elif
[No Abstract Available]
Citation - WoS: 3
Rectangular Shaped, Dual-Frequency Antenna With a Single Shorting Pin
(Turgut Ozal Univ, 2012) Kapusuz, K. Yavuz; Can, Sultan; Aydin, Elif
In this study, a dual-frequency rectangular patch antenna is demonstrated. The dual frequency operation is obtained via inserting a shorting pin to the rectangular patch coaxial fed antenna. The first and the second resonant frequencies are presented for different substrate, thickness, and side length values. The effect of the shorting pin is also observed and the results are presented. The results obtained from this study are compared with the ones in the literature and satisfactory agreement is obtained. While 4.75% average error is achieved for the first resonant frequency, the average error for the second resonant frequency is 4.49%. The relation of the first and the second resonant frequency with the antenna parameters are evaluated and presented.
Citation - WoS: 8
Citation - Scopus: 12
Computation and Optimization of Resonant Frequency and Input Impedance of a Coax-Fed Circular Patch Microstrip Antenna
(John Wiley & Sons inc, 2007) Gurel, Cigdem Seckin; Aydin, Elif; Yazgan, Erdem
Microstrip antennas are important elements of today's wireless communication networks. In their various applications, it is critical to provide wide hand operation around the resonant frequency providing good impedance match between the antenna element and the feed. In this study, new, simple, arid accurate computation of resonant frequency and input impedance of double-layered, coaxial fed circular disk microstrip antenna with air gap is performed. In the analysis, new effective radius and permittivity expressions are used in simple and modified form including modal effects. Then, a new approach is proposed to provide input impedance matching (it resonant frequency via the application of microgenetic algorithm for wide hand operation. The accuracy of theoretical calculations and impedance matching approach are presented for various,structural parameters and operational modes of the antenna. (C) 2007 Wiley Periodicals, Inc.
Low Signature UAVs: Radar Cross Section Analysis, Simulation, and Measurement in X-Band
(Springer London Ltd, 2025) Unalir, Dizdar; Yalcinkaya, Bengisu; Aydin, Elif
The increasing prevalence of unmanned aerial vehicles (UAVs) is driving the development of radar systems capable of detecting them. This hampers the deployment of UAVs in military operations. While radar cross section reduction (RCSR) can be a valuable solution, the research on this subject is inadequate. This paper presents an RCSR approach adopting a shaping technique for UAVs, demonstrating the proposed approach's efficacy through simulations and actual experimental measurements performed in X-Band on a four-legged UAV model. Using electromagnetic computational instruments, the shaping is applied to the designed UAV model with parameter-based simulations, the simulated radar cross section (RCS) values are derived, and the comparative analysis of these instruments is conducted. Experimental measurements are performed in laboratory conditions using a vector network analyzer. Actual measurement results are validated by simulative findings with the examination of the influence of frequency, polarization, and aspect angle on RCS. The demonstrated measuring approach allows cost-effective and easily applicable research on RCS in X-Band, a commonly utilized frequency range in military. An average RCSR of 10 dBsm has been accomplished with the presented shaping approach.
COMPARISON OF COMPUTER-BASED PROPAGATION MODELS WITH EXPERIMENTAL DATA COLLECTED IN AN URBAN AREA AT 1800 MHz
(Ieee, 2015) Acar, Tarik; Caliskan, Fatma; Aydin, Elif
Nowadays a lot of models are set for the efficient and economic usage of frequency band since the band is a limited source. Therefore, the propagation models created for this purpose were studied in the literature. These models are Free Space Path Loss (Fspl) + Reflection plus Multiple Diffraction (RMD), COST-Hata and COST-WI models. In order to compare the success of the models, electric field strength measurements were taken in a chosen district (Mustafa Kemal Mahallesi Ankara, Turkey) where an irregular structure style can be observed. First set of measurements were recorded at random coordinates and second set of measurements were collected by the following coordinates tracking on a single line. As a conclusion, measured values were compared with the results which were taken from the mentioned models with graphical presentations. The most appropriate model was tried to be found and as another aim of the study, a correction factor was generated as a modification for COST-Hata propagation model.
Comparative Assessment and Performance Analysis of Interference Mitigation Techniques for Co-Existent Non-Geostationary and Geostationary Satellites
(Wiley, 2024) Ozturk, Faik; Aydin, Elif; Kara, Ali
In recent years, technological developments with user demands, reduced production, and launch costs have rapidly increased the number of Low Earth Orbit (LEO) satellites in space. Since LEO satellites use the same frequency band as existing Geostationary Earth Orbit (GEO) satellites, the interference coordination between the two satellite networks is vital. In order to minimize the co-existent interference between these satellite networks, studies perform on different interference mitigation strategies. In this paper, analysis and comparative assessment of these interference mitigation techniques are presented for the co-existent Non-Geostationary Earth (NGEO) and GEO systems. More specifically, power control (PC) and spatial isolation-based link adaptation (SILA) techniques are studied comparatively for the performance evaluation. It is shown that the communication link bandwidth is more efficiently utilized in the SILA technique when compared with the PC technique. Moreover, the multi-objective optimization problem (MOP) approach in the SILA technique is demonstrated to be more effective when compared with the single-objective optimization problem (SOP) approach used in the PC technique as the simultaneous prioritizing objective functions outperforms single prioritization. Finally, it is shown that when the PC technique is applied together with the SILA technique, the exclusive angle (EA) can be reduced up to 8% for 100 Mbps, and 8.5% for 200 Mbps transmission bit rates in different operational scenarios. The presented performance evaluation in this paper may help the satellite operator or decision-maker gain insights on which mitigation technique can be used in the case of a co-existent interference. This paper proposes analysis and comparative assessment of interference mitigation techniques for the co-existent Non-Geostationary Earth (NGEO) and Geostationary Earth Orbit (GEO) systems. Spatial isolation-based link adaptation (SILA) and power control (PC) techniques are studied comparatively for the performance evaluation. The obtained optimization results show that the communication link bandwidth is more efficiently utilized in the SILA technique when compared with the PC technique because of the simultaneous prioritizing of objective functions. image

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