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    BLOCKBOX: Blockchain based black box designing and modeling
    (Wiley, 2024) Korkuç, Çağatay; Korkmaz, Nilay Aytas; Genç, Yasin; Akkoc, Ahmet; Afacan, Erkan; Yazgan, Erdem
    With the development of technology, data has become more accessible. The storage of critical and valuable information is getting harder and harder with the increase of cyber attacks and vulnerabilities of network and internet. The centralized storage of data causes security and privacy problems. As a remedy to these problems, blockchain has occurred. The reliability, transparency, integrity and confidentiality of the data have been increased with the blockchain technology. Blockchain maintains the immutability of the data with cryptographic hash algorithms. The data is kept in distributed structures with the consensus algorithms so that it is not lost. Projects and studies using blockchain technology have shown that data stored in centralized structures is not as reliable as data that is distributed and secured by cryptographic algorithms, smart contracts, and consensus. The data of flights, which is a critical data, has a great place in world transportation. The parameters inside the black boxes guide us on why the aircrafts have crashed: whether the responsibility belongs to the manufacturer, to the pilot, or to the aircraft technicians. In this way, the real reasons of the accident may be determined and measures can be taken for the accidents that may occur afterwards. In addition, the safe delivery of all black box data to the interested parties and its storage in a way that is immutable will not only benefit to the manufacturer's self-development by processing the data, but also help flight companies to find optimum flight data. Both the flight companies and the manufacturer will be able to read the black box data, thus the suspicion of data manipulation will be eliminated and the data will become more transparent. In this study, a system is proposed in which an aircraft's black box data can be saved safely and securely with the help of blockchain technology.
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    Genetik Algoritma ile Genişbant Anten Tasarimi Wideband Array Design with Genetic Algorithm
    (Institute of Electrical and Electronics Engineers Inc., 2023) Dikdere, Mustafa Oner; Genc, Yasin; Korkmaz, Nilay Aytas; Akkoc, Ahmet; Afacan, Erkan; Yazgan, Erdem
    The importance of big data transfer and higher speed communication is increasing day by day in communication systems. Antennas are key objects in wireless communication systems. Antenna specifications can be designed according to wireless communication requirements. Genetic algorithms, one of the types of heuristic algorithms, play an important role in antenna design. In genetic algorithms, the proposed near-best design is given as a result to obtain the desired antenna properties. In this study, the microstrip linear antenna array was designed with the genetic algorithms, and reached a better specification than the frequency range determined by the National Communications Commission (FCC). © 2023 IEEE.
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    Higher Order Taylor and Golomb Costas Arrays
    (Institute of Electrical and Electronics Engineers Inc., 2023) Gudek, Mesut; Genc, Yasin; Korkmaz, Nilay Aytas; Akkoc, Ahmet; Afacan, Erkan; Yazgan, Erdem
    Costas arrays, which have been defined as special permutation matrices, have widespread applications in many fields. Low probability of intercept (LPI) radars are used to detect targets without being detected by hostile elements. Frequency Shift Keying is one of the modulation types used in LPI radars. Costas arrays are used to generate frequency sets for LPI radars. These frequency sets with frequency shift keying waveforms are mostly generated using methods based on finite field theory. In this study, a comprehensive search for higher order (up to 5000) variational Costas arrays have been performed with the software developed using C++ programming language. The results obtained are presented in tables. © 2023 IEEE.
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    Time-Invariant and Localized Secure Reception With Sequential Multicarrier Receive-FDA
    (IEEE-Inst Electrical Electronics Engineers Inc, 2023) Akkoc, Ahmet; Korkmaz, Nilay Aytas; Genc, Yasin; Afacan, Erkan; Yazgan, Erdem
    Secure communication in the physical layer (PHY) using frequency diverse array (FDA) antennas has become a prominent research topic in recent years due to the unique range-;angle-dependent beam pattern exhibited by FDAs. However, the time-varying and periodic nature of the FDA beam pattern prevents the achievement of a time-invariant range-angle-focused beam pattern. Consequently, a range-angle-focused beam is only achieved at a specific time instant. Therefore, it is not yet possible to focus a beam on a specific point or area in space permanently in a time-invariant manner, due to both natural propagation mechanisms and the independent time parameter. Once a wave is transmitted, time variation cannot be altered. Thus, for the FDA beam pattern, it continues to propagate over time indefinitely. However, in the case of receiving, the time parameter is under the control of the receiver. The receiver can set the time at which the incoming wave is sampled or acquired. In this study, a cross-linear array structure called the sequential multicarrier receive FDA (SMCR-FDA) and a relevant methodology are proposed to obtain a three-dimensionally localized time-invariant range-angle-focused receive beam pattern. Additionally, several novel concepts, including the cross-linear array structure, the secure reception concept, and the positional modulation (PoM) technique, are introduced.