Kara, Ali

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Profile URL
https://hdl.handle.net/20.500.14411/7682
Name Variants
Kara, A
Kara, A.
Kara,A.
Ali, Kara
Kara, Ali
K., Ali
A.,Kara
A., Kara
K.,Ali
Job Title
Profesör Doktor
Email Address
ali.kara@atilim.edu.tr
Main Affiliation
Department of Electrical & Electronics Engineering
Status
Former Staff
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Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID

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AFFORDABLE AND CLEAN ENERGY
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INDUSTRY, INNOVATION AND INFRASTRUCTURE
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Scholarly Output

169

Articles

75

Citation Count

657

Supervised Theses

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Now showing 1 - 10 of 170
  • Thumbnail Image
    Conference Object
    Citation - Scopus: 4
    Distance Laboratory Applications Errl: a Study on Radio Communication in Electronic Field
    (2008) Aydin,C.Ç.; Türkmen,G.; Özyurt,E.; Aydm,E.U.; Çaǧiltay,N.E.; Özbek,M.E.; Kara,A.; Department of Electrical & Electronics Engineering; Computer Engineering
    In the last decade, the effect of internet usage in education is gradually increased. When we look from academic perspective, the new technologies provided alternatives for students learning. As distance education becomes important everyday, the indispensable elements of teaching and education, laboratories must be reachable via remote connection. Consequently, the education that is going to be given to the students will be more flexible with respect to place and time constraints and students can reach laboratory facilities at any time and anywhere not only in lectures and practical hours. In this study, European Remote Radio Laboratory (ERRL) which is a distance remote Radio Frequency (RF) laboratory designed for electrical-electronics students, is described generally. The software architecture, infrastructure and experiment that can be done with a remote connection have been described.
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    Article
    ISAR Imaging of Drone Swarms at 77 GHz
    (Tubitak Scientific & Technological Research Council Turkey, 2025) Coruk, Remziye Busra; Kara, Ali; Aydin, Elif; Department of Electrical & Electronics Engineering
    The 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.
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    Conference Object
    Citation - WoS: 2
    Citation - Scopus: 3
    Design 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 Engineering; Department of Electrical & Electronics Engineering; Electrical-Electronics Engineering
    This 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.
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    Article
    Citation - WoS: 25
    Citation - Scopus: 30
    A Wavelet-Based Feature Set for Recognizing Pulse Repetition Interval Modulation Patterns
    (Tubitak Scientific & Technological Research Council Turkey, 2016) Gencol, Kenan; At, Nuray; Kara, Ali; Department of Electrical & Electronics Engineering
    This paper presents a new feature set for the problem of recognizing pulse repetition interval (PRI) modulation patterns. The recognition is based upon the features extracted from the multiresolution decomposition of different types of PRI modulated sequences. Special emphasis is placed on the recognition of jittered and stagger type PRI sequences due to the fact that these types of PRI sequences appear predominantly in modern electronic warfare environments for some specific mission requirements and recognition of them is heavily based on histogram features. We test our method with a broad range of PRI modulation parameters. Simulation results show that the proposed feature set is highly robust and separates jittered, stagger, and other modulation patterns very well. Especially for the stagger type of PRI sequences, wavelet-based features outperform conventional histogram-based features. Advantages of the proposed feature set along with its robustness criteria are analyzed in detail.
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    Article
    Citation - Scopus: 8
    Multipath Exploitation in Emitter Localization for Irregular Terrains
    (Czech Technical University, 2019) Dalveren,Y.; Kara,A.; Department of Electrical & Electronics Engineering
    Electronic Support Measures (ESM) systems have many operational challenges while locating radar emitter's position around irregular terrains such as islands due to multipath scattering. To overcome these challenges, this paper addresses exploiting multipath scattering in passive localization of radar emitters around irregular terrains. The idea is based on the use of multipath scattered signals as virtual sensor through Geographical Information System (GIS). In this way, it is presented that single receiver (ESM receiver) passive localization can be achieved for radar emitters. The study is initiated with estimating candidate multipath scattering centers over irregular terrain. To do this, ESM receivers' Angle of Arrival (AOA) and Time of Arrival (TOA) information are required for directly received radar pulses along with multipath scattered pulses. The problem then turns out to be multiple-sensor localization problem for which Time Difference of Arrival (TDOA)-based techniques can easily be applied. However, there is high degree of uncertainty in location of candidate multipath scattering centers as the multipath scattering involves diffuse components over irregular terrain. Apparently, this causes large localization errors in TDOA. To reduce this error, a reliability based weighting method is proposed. Simulation results regarding with a simplified 3D model are also presented. © 2019 RADIOENGINEERING.
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    Article
    Citation - WoS: 8
    Citation - Scopus: 13
    A Study on the Performance Evaluation of Wavelet Decomposition in Transient-Based Radio Frequency Fingerprinting of Bluetooth Devices
    (Wiley, 2022) Almashaqbeh, Hemam; Dalveren, Yaser; Kara, Ali; Department of Electrical & Electronics Engineering
    Radio frequency fingerprinting (RFF) is used as a physical-layer security method to provide security in wireless networks. Basically, it exploits the distinctive features (fingerprints) extracted from the physical waveforms emitted from radio devices in the network. One of the major challenges in RFF is to create robust features forming the fingerprints of radio devices. Here, dual-tree complex wavelet transform (DT-CWT) provides an accurate way of extracting those robust features. However, its performance on the RFF of Bluetooth transients which fall into narrowband signaling has not been reported yet. Therefore, this study examines the performance of DT-CWT features on the use of transient-based RFF of Bluetooth devices. Initially, experimentally collected Bluetooth transients from different smartphones are decomposed by DT-CWT. Then, the characteristics and statistics of the wavelet domain signal are exploited to create robust features. Next, the support vector machine (SVM) is used to classify the smartphones. The classification accuracy is demonstrated by varying channel signal-to-noise ratio (SNR) and the size of transient duration. Results show that reasonable accuracy can be achieved (lower bound of 88%) even with short transient duration (1024 samples) at low SNRs (0-5 dB).
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    Correction
    Characterization of Lead Glazed Potteries From Smyrna (izmir/Turkey) Using Multiple Analytical Techniques; Part I: Glaze and Engobe (vol 40, Pg 2143, 2014)
    (Elsevier Sci Ltd, 2014) Ozcatal, M.; Yaygingol, M.; Issi, A.; Kara, A.; Turan, S.; Okyar, F.; Minceva-Sukarova, B.; Department of Electrical & Electronics Engineering
    [No Abstract Available]
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    Master Thesis
    Doğrusal Kablosuz Algılayıcı Ağlar için Bir Eşzamanlama Algoritması ve Link Katmanı Protokolün Gerçeklenmesi
    (2020) Imran, Md Abdullah Al; Kara, Ali; Department of Electrical & Electronics Engineering
    Eşzamanlama, Kablosuz Algılayıcı Ağlar (KAA) gibi dağıtılmış ağ sistemlerinde büyük önem taşımaktadır. KAA'lar dağıtılmış varlıkların ve olayların koordinasyonu ve korelasyonu için eşzamanlamayı yaygın olarak kullanır. Tipik olarak, enerji, depolama, hesaplama ve bant genişliği gibi sınırlı kaynaklar, ortam koşulları ve uygulamaya özel gereksinimlerle birleştirilmiş sınırlı özellikleri nedeniyle, geleneksel eşzamanlama yöntemlerini olanaksız kılabilir. Bu nedenle, form faktörü, hassasiyet, işlem süresi ve gücü, bellek, trafik, verimlilik ve ölçeklenebilirlik gibi çok sayıda tasarım parametresi, KAA'ların eşzamanlanmasında çalışılmaktadır. Bu tez çalışmasında, doğrusal KAA'larda eşzamanlanma çalışılmış ve buna yönelik bütünsel bir protokol geliştirilerek deneysel sonuçlar irdelenmektedir. Geliştirilen protokol, düğümler üzerinden veri toplama ve basit hata işleme özellikleri ile donatılmıştır. Deneysel çalışmalar sonucunda, geliştirilen protokol ve eşzamanlama yönteminin etkinliği irdelenmiş ve ağ ömrünün optimizasyonlar ile arttırılabildiği gösterilmiştir. Bu kapsamda, eşzamanlamadaki kritik parametreler olan ofset ve zamanda kaymaların eşzamanlama doğruluğuna etkisi incelenmiştir. Yapılan testlerde, daha küçük eşzamanlama pencereleri ile daha yüksek bir eşzamanlama doğruluğu sağlanmaktadır. Buna bağlı olarak enerji tüketimi de optimize edilebilmektedir.
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    Conference Object
    Miniaturized 2.4 Ghz Antenna Design for Uav Communication Link;
    (Institute of Electrical and Electronics Engineers Inc., 2020) Yilmaz,V.S.; Kara,A.; Aydin,E.; Department of Electrical & Electronics Engineering; Electrical-Electronics Engineering
    In many communications applications, unlike conventional antennas, lightweight, flexible, small antennas that can adapt to mechanical and industrial constraints are required. In this study, the results of antenna design operating at 2.4 GHz are presented for use in Unmanned Aerial Vehicle (UAV) tele command links. In the parametric and optimization studies carried out on the antenna, it is aimed to increase the gain while keeping the size as small as possible. The requirements of the industry, such as light, aesthetics, miniature and high gain aspects of the antenna were targeted in the design process. Finally, an antenna of 55.2x88 mm size and 7dB gain was achieved using commercial electromagnetic design tools. The designed antenna become satisfying industrial requirements with these features. © 2020 IEEE.
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    Article
    Citation - WoS: 4
    Heterogeneity in Classes: Cooperative Problem-Solving Activities Through Cooperative Learning
    (Fac Teacher Education, 2014) Cigdemoglu, Ceyhan; Kapusuz, Kamil Yavuz; Kara, Ali; Department of Electrical & Electronics Engineering; Public Relations and Advertising
    Teachers, from primary schools to college, experience challenges regarding both increased class sizes and a greater diversity of students having a broad spectrum of abilities, interests, needs, and goals. The aim of this paper is to investigate the effect of cooperative learning through Cooperative Problem-Solving (CPS) activities on homogenous and heterogeneous grouping in an engineering course. As a mixed method design, the study utilized both quantitative and qualitative data. The participants, 47 engineering students selected conveniently, were enrolled in a communication systems course. The analysis of the quantitative data indicated that no significant difference (p=.791) exists between the ways in which the students in homogenous and the students in heterogeneous group understand communication systems. In order to reveal the perceptions of students regarding the implementation, they were interviewed at the end of the semester. The qualitative data obtained from these interviews suggests that students prefer heterogeneous to homogenous grouping. The findings also imply that further research should concentrate on heterogeneous grouping strategies and more detailed qualitative data in order to reveal what kind of patterns emerge from students' interactions in different groupings.