Yazar "Afacan, Erkan" seçeneğine göre listele

Listeleniyor 1 - 13 / 13
  • [ X ]
    Öğe
    A Novel Identity-Based Privacy-Preserving Anonymous Authentication Scheme for Vehicle- to-Vehicle Communication
    (Kaunas Univ Technology, 2023) Genc, Yasin; Korkuc, Cagatay; Aytas, Nilay; Afacan, Erkan; Sazli, Murat H.; Yazgan, Erdem
    This paper proposes a novel bilinear pairing-free identity-based privacy-preserving anonymous authentication scheme for vehicle-to-vehicle (V2V) communication, called NIBPA. Today, vehicular ad hoc networks (VANETs) offer important solutions for traffic safety and efficiency. However, VANETs are vulnerable to cyberattacks due to their use of wireless communication. Therefore, authentication schemes are used to solve security and privacy issues in VANETs. The NIBPA satisfies the security and privacy requirements and is robust to cyberattacks. It is also a pairing-free elliptic curve cryptography (ECC)-based lightweight authentication scheme. The bilinear pairing operation and the map-to-point hash function in cryptography have not been used because of their high computational costs. Moreover, it provides batch message verification to improve VANETs performance. The NIBPA is compared to existing schemes in terms of computational cost and communication cost. It is also a test for security in the random oracle model (ROM). As a result of security and performance analysis, NIBPA gives better results compared to existing schemes.
  • [ X ]
    Öğe
    A Novel Identity-Based Privacy-Preserving Anonymous Authentication Scheme for Vehicle-to-Vehicle Communication
    (Kauno Technologijos Universitetas, 2023) Genc, Yasin; Korkuc, Cagatay; Aytas, Nilay; Afacan, Erkan; Sazli, Murat H.; Yazgan, Erdem
    This paper proposes a novel bilinear pairing-free identity-based privacy-preserving anonymous authentication scheme for vehicle-to-vehicle (V2V) communication, called “NIBPA”. Today, vehicular ad hoc networks (VANETs) offer important solutions for traffic safety and efficiency. However, VANETs are vulnerable to cyberattacks due to their use of wireless communication. Therefore, authentication schemes are used to solve security and privacy issues in VANETs. The NIBPA satisfies the security and privacy requirements and is robust to cyberattacks. It is also a pairing-free elliptic curve cryptography (ECC)-based lightweight authentication scheme. The bilinear pairing operation and the map-to-point hash function in cryptography have not been used because of their high computational costs. Moreover, it provides batch message verification to improve VANETs performance. The NIBPA is compared to existing schemes in terms of computational cost and communication cost. It is also a test for security in the random oracle model (ROM). As a result of security and performance analysis, NIBPA gives better results compared to existing schemes. © 2023 Kauno Technologijos Universitetas. All rights reserved.
  • [ X ]
    Öğe
    An interval-valued spherical fuzzy CIMAS-WISP group decision-analytic model for blockchain platform selection in digital projects
    (Elsevier, 2024) Kara, Karahan; Yalcin, Galip Cihan; Simic, Vladimir; Korkuc, Cagatay; Cicek, Ilhan; Afacan, Erkan; Pamucarg, Dragan
    Digital projects aspiring to reach target audiences are executed through decentralized and trustworthy block- chain platforms (BPs). Once the objectives and target audience of a digital project are defined, the selection of suitable BPs is undertaken. The primary objective of this research is to develop a decision support system that aids in the selection of BPs for transferring digital data and assets. Numerous quantitative parameters determine the performance of BPs, alongside qualitative parameters indicating their performance. In this study, the aim is to determine the performance of BPs based on both qualitative and quantitative parameters. Within this scope, a multi-criteria decision-making approach and interval-valued spherical fuzzy (IVSF) sets are adopted. IVSF sets are utilized to determine expert importance levels. The IVSF-criteria importance assessment (CIMAS) method is introduced for the weighting of criteria. IVSF-CIMAS enables the determination of reliability levels in calculating criterion weights. The IVSF-simple weighted sum product (WISP) method is formulated to obtain the performance ranking of BPs. Thus, in this research, the IVSF-CIMAS-WISP hybrid model is developed, and an algorithm for this novel decision-analytic model is presented. A case study is developed focusing on BP selection for a digital project to demonstrate the applicability of the proposed hybrid model. The robustness of IVSF-CIMAS
  • [ X ]
    Öğe
    BLOCKBOX: Blockchain based black box designing and modeling
    (Wiley, 2024) Korkuc, Cagatay; Korkmaz, Nilay Aytas; Genc, 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.
  • [ X ]
    Öğe
    Digital Image Encryption Using Elliptic Curve Cryptography: A Review
    (Institute of Electrical and Electronics Engineers Inc., 2022) Habek, Muhammed; Genc, Yasin; Aytas, Nilay; Akkoc, Ahmet; Afacan, Erkan; Yazgan, Erdem
    Today, digital images are used in many different applications. They can be social media applications or critical applications such as military and medical. However, cyber attacks or privacy problems also cause serious security problems for digital images. Therefore, various methods are proposed to ensure privacy and security. The first science that comes to mind is cryptography. It is a science of encryption. Encryption methods ensure the privacy of data. Many encryption methods are used to ensure the privacy and accuracy of the digital images. This paper reviews the encryption method based on elliptic curve cryptography for digital image encryption. This review describes the parameters and security attacks that affect the performance of digital image encryption. In addition, existing studies are reviewed. Thus, this paper is about the usefulness of both design criteria to be considered for new digital image encryption methods and comparing existing studies. © 2022 IEEE.
  • [ X ]
    Öğe
    Direction of arrival estimation in time modulated linear arrays using matrix pencil method with single snapshot and optimized time steps
    (Elsevier Gmbh, 2022) Aytas, Nilay; Afacan, Erkan; Inanc, Nihat
    The direction of arrival estimation by the time modulated linear array with a proposed novel approach has been analyzed and proven. By merging Matrix Pencil method with time modulated linear array, a great advantage has been obtained by the virtue of using a single snapshot. A new formulation is developed by the authors which combines the Time Modulation and Matrix Pencil methods. The time steps were optimized using differential evolution algorithm for the estimation of the angle of incidence. The effects of the noise level, the number of signal sources, the number of antenna elements and different angles of incidence were examined with the simulations and comparisons were presented. Compared to traditional methods, the simulation results show that the proposed novel approach maintains significant advantages from the viewpoint of estimation accuracy, especially for scenarios with single snapshot number and low SNR.
  • [ X ]
    Öğe
    ELCPAS: A new efficient lightweight certificateless conditional privacy preserving authentication scheme for IoV
    (Elsevier, 2023) Genc, Yasin; Aytas, Nilay; Akkoc, Ahmet; Afacan, Erkan; Yazgan, Erdem
    This paper proposes a new efficient certificateless conditional privacy preserving authentication (CL-CPPA) scheme named ELCPAS, which is pairing-free, energy-efficient, lightweight which uses elliptic curve cryptography (ECC) for internet of vehicles (IoV). The ELCPAS is based on the certificateless signature scheme that eliminates the key escrow problem, which is the drawback of identity-based encryption. It performs batch message verification with a very efficient method which minimizes the delays in the message verification phase. In our proposed scheme, users (vehicle etc.) do not need to communicate with central units during each message signing. Thus, the computational load and connection problems in the central units are minimized. It is also quite fast as it does not use the bilinear pairing and map-to-point operations. The performance evaluation shows that ELCPAS has efficiency in scope of computation cost, communication cost and energy consumption cost compared to other existing schemes. The security evaluation is performed according to the random oracle model (ROM) and the proposed ELCPAS scheme has been shown to be secure. In addition, it provides security requirements and it is resistant to cyber-attacks. The results of the analyses performed according to the security criteria show that it is secure.(c) 2022 Elsevier Inc. All rights reserved.
  • [ X ]
    Öğe
    Elliptic Curve Cryptography for Security in Connected Vehicles
    (IEEE, 2022) Genc, Yasin; Habek, Muhammed; Aytas, Nilay; Akkoc, Ahmet; Afacan, Erkan; Yazgan, Erdem
    The concept of a connected vehicle refers to the linking of vehicles to each other and to other things. Today, developments in the Internet of Things (IoT) and 5G have made a significant contribution to connected vehicle technology. In addition to many positive contributions, connected vehicle technology also brings with it many security-related problems. In this study, a digital signature algorithm based on elliptic curve cryptography is proposed to verify the message and identity sent to the vehicles. In the proposed model, with the anonymous identification given to the vehicle by the central unit, the vehicle is prevented from being detected by other vehicles and third parties. Thus, even if the personal data produced in the vehicles is shared, it cannot be found which vehicle it belongs to.
  • [ X ]
    Öğe
    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.
  • [ X ]
    Öğe
    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.
  • Küçük Resim
    Öğe
    Signal and Noise Subspace Decomposition for a Linear Antenna Array Using SVD
    (Ieee, 2018) Aytaş, Nilay; Afacan, Erkan; İnanç, Nihat
    In the vast majority of signal processing applications, the signal is intended to be analyzed to obtain a variety of data from the signal. It is decomposed into signal subspaces to perform this analysis. The noise in the signal during analysis is undesirable. If the signal incoming to an antenna array contains noise, it should be filtered before processing signal. In this study, we have tried to divide the uniform linear antenna array into subspaces of incoming signals from multiple signal sources with various frequencies, noise and arrival angles. The Singular Value Decomposition (SVD) method is used to separate the signal subspace and noise subspace. According to the singular values obtained, the information about the frequencies of the signals and whether the signal contains noise. Also, the number of sources can be estimated by means of singular values.
  • [ X ]
    Öğe
    The Application of Matrix Pencil Method for Direction Finding Using a Linear Antenna Array
    (IEEE, 2021) Aytas, Nilay; Afacan, Erkan; Inanc, Nihat
    The estimation of the direction of signal sources is used especially in military applications such as radar systems, locating systems, military warfare systems, and in civil applications such as mobile communication systems. The systems that used to only determine the location of a single signal source have obtained the ability to simultaneously detect the direction and location of signals from multiple signal sources following the development of subspace techniques. Matrix Pencil method is a method used in subspace analysis of the signal, in this study, it is aimed to estimate the direction of arrival of the signals impinging from one or more signal sources to the antenna array using this method. The analysis showed that high accuracy results have been obtained in the estimation of the direction of arrival the signals impinging to the antenna array by Matrix Pencil method.
  • [ X ]
    Öğe
    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.