Elektrik Elektronik Mühendisliği Bölümü

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Alternative Enhancement of Associativity Based Routing (Aeabr) for Mobile Networks
(Springer, 2010) Preveze, Barbaros; Safak, Aysel
This study proposes an alternative enhancement for the Enhanced Associativity Based Routing (EABR) method which is a derivation of ABR (Associativity Based Routing) by relative speed and relative distance estimation using the received power strength (RPS) of the nodes. In this study, it is shown that EABR outperforms some other well known protocols. The performance of EABR is improved in terms of number of route reconstructions (RRC) and connected status percentage (CSP). Message overhead and bandwidth utilization is also investigated.
Citation - WoS: 1
Citation - Scopus: 1
Enhancing Quantum Correlation at Zero-If Band by Confining the Thermally Excited Photons: Inp Hemt Circuitry Effect
(Springer, 2023) Salmanogli, Ahmad
The microwave quantum correlation as a crucial issue in quantum technology is analyzed and studied. An open quantum system operating at 4.2 K is designed in which InP HEMT as the nonlinear component couples two external oscillators. The quantum theory is applied to analyze the system completely. The Lindblad Master equation is used to analyze the time evolution of the expanded closed system that covers the environmental effects. In the following, the state of the system defined is determined in terms of the ensemble average state using the density matrix; then, the ensemble average of the different operators is calculated. Accordingly, the covariance matrix of the quantum system is derived, and the quantum discord as a key quantity to determine the quantum correlation is calculated. As an interesting point, the results show that InP HEMT mixes two coupling oscillator modes so that the quantum correlation is created at different frequency productions, especially the zero-IF band. Nonetheless, the main point is that one can strongly manipulate the quantum correlation in the zero-IF using circuitry engineering. It is established by increasing the operational frequencies in the quantum system leading to dramatically limiting the thermal noise since the zero-IF band remains unchanged.
Citation - WoS: 22
Citation - Scopus: 19
Laser Array Beam Propagation Through Liver Tissue
(Springer, 2020) Baykal, Yahya; Ata, Yalcin; Gokce, Muhsin Caner
Laser array beam propagating through mouse liver tissue is investigated. The turbulence power spectrum of the liver tissue is employed in the extended Huygens-Fresnel method to obtain an optical intensity profile and beam broadening at the observation point in biological liver tissue. Variations of the beam profile and the beam broadening are simulated based on the number of beamlets, source size, wavelength and the ring radius of the array. A biological tissue, illuminated by the laser array beam, exhibits different beam profiles and beam spot radius variations when the number of beamlets, source size, wavelength and the ring radius of the laser array beam are varied. Examining these variations observed in the propagated optical beam and comparing them with the test cases, abnormalities such as cancer and tumor in a biological liver tissue can be diagnosed.
Citation - WoS: 5
Citation - Scopus: 6
Mitigation of Atmospheric Turbulence on Up and Downlink Optical Communication Systems Using Receiver Diversity and Adaptive Optics
(Springer, 2022) Gokce, Muhsin Caner; Baykal, Yahya; Ata, Yalcin
Improvement in the performance of uplink and downlink optical communication systems by means of receive diversity and adaptive optics correction is investigated. We develop a communication system model using adaptive optics correction in the transmitter and maximum ratio combining diversity technique in the receiver. The effect of adaptive optics correction modes, receive diversity, zenith angle, link length, wind speed and the height of transmitter/receiver on the ground are evaluated. Performance improvement is observed with both adaptive optics correction and the receive diversity. It is aimed to provide researchers an option to determine the method they will use to reduce the effect of turbulence. As the numerical values of the main results, we report that adaptive optics correction with 5 mode Zernike removal reduces BER from 10(-8) to 10(-10) for one receiver. When the number of receivers is 6, BER is found to reduce from 10(-6) to 10(-12). The results obtained in this study can be beneficial to optimize the design of the slant path uplink and downlink optical communication links between the ground and low-orbit satellites that are exposed to atmospheric turbulence.
Citation - Scopus: 1
A Novel Cognitive Method for Throughput Improvement of Mobile Multi-Hop Ad Hoc Networks
(Springer, 2015) Preveze, Barbaros
We had previously defined a novel cognitive method for throughput improvement of IEEE 802.16j mobile multi-hop ad-hoc network which enables better management of the spectral access and buffer management of the nodes in the network. By this method we had minimized the packet loss ratio and improved the throughput of IEEE 802.16j network. In this study, a novel cognitive buffer management algorithm is proposed that arranges the packets stored in the buffers of the nodes in a probabilistic way and selects correct packet of the correct node to transmit first to provide fewer packet losses and also fewer average hop-counts for more throughputs. It is shown that the novel proposed buffer management algorithm provides about 19.45 % more throughput improvement (on average) with respect to the results evaluated by the buffer management algorithm used before (which was also shown to provide 12 % throughput improvement with respect to a First In First Out buffer management algorithm). All the results evaluated in this study are also confirmed by the results of analytical calculations, the results of the developed simulation program and the results evaluated in the literature.
Citation - Scopus: 2
A Novel High Performance Routing Algorithm for Mobile Multi-Hop Tunneling Networks
(Springer, 2020) Preveze, B.
By the increased number of mobile devices, the demand of high speed connection oriented tunneling networks also increases. But, in mobile tunneling networks, the full route will have to be reconstructed more frequently because of more frequent route failures, where the requirements for extra route reconstructions (RRC) will cause extra delay and a decreased system throughput. In this work, a novel routing algorithm, optimum path routing (OPR) is proposed to extend the route life time of mobile multi hop tunneling networks and to increase the system throughput. On the other hand, as the most recent works in the literature indicate that, one of the greatest challenges of tunneling networks is to provide the network flexibility by instant adaptation on changing network conditions to keep the delay at lowest levels even in case of high traffic loads or node failures. To solve the aforementioned flexibility problem of the tunneling networks, a novel algorithm applicable to all kinds of routing algorithms called “avoid congested nodes (ACN)” is proposed. The results show that, the OPR algorithm proposed to increase the route life has succeeded in decreasing the RRC delay by 84% and improving the throughput by 20.17% with respect to the Fastest Path routing algorithm in the literature. And the ACN algorithm, proposed to provide a rapid adaptation of the nodes to the changing traffic conditions, has also succeeded in carrying back the throughput of the network with traffic load from 75.5% of its best performance evaluated with no traffic to its 94%. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
A Novel Solution for Network Flexibility Problem in Mobile Multi-Hop Tunneling Networks
(Springer, 2023) Preveze, Barbaros
Since the network throughput performance is limited by the available technology limits, there are too many attempts in the literature to improve the throughput performance of the network by modifying the routing algorithms currently in use. Although application of the tunneling on IP networks provides reserved paths for the higher priority packet streams and succeeds in providing faster communication performances, it is also determined in the literature that, the greatest up to date problem of tunneling networks is the flexibility problem, which is defined as the problem of difficulty to have minimal delay and highest throughput when congestions or node failures occur and the throughput decreases due to high traffic loads on the network. sIn this work, a high performance solution, called LB-ACN (Location Based- Avoid Congested Node) is proposed to solve this flexibility problem and to compensate the increased delay which came up due to the high traffic load and also due to inflexible tunneling network structure, considering the locations of the nodes in addition to their traffic loads. And it is shown that, it is succeeded to carry the throughput of the highly traffic loaded network back to 48.6 Mbps from 36.9 Mbps by about 31.7% performance improvement for which we could improve it from 36.9 Mbps up to 45.9 Mbps by 24.3% using the proposed ACN (Avoid Congested Node) algorithm in our previous work. As a result, we have succeeded in having about 7.4% more improvement on throughput performance in comparison with the previously proposed ACN algorithm.
Quantum Dot Transition Rate Modifying by Coupling To Lattice Plasmon
(Springer, 2023) Salmanogli, Ahmad; Gecim, H. Selcuk; Hatem, Sude
In this study, a plasmonic system coupled to a quantum dot is defined to generate the entanglement between two non-simultaneous emitted output modes. The quantum dot with three energy levels creates two different transition rates by which non-simultaneous photons are emitted. Thus, it seems that the entanglement between two emitted modes is forbidden. However, the simulation results show the entanglement between the output modes. It is because the original transition rates of the quantum dot are modified due to the lattice plasmon coupling effect. It means that the effective transition rate affected by the lattice plasmon plays a key role. The lattice plasmon coupling to quantum dot at some locations leads to a simultaneous transition by which the entanglement between output modes is established. The entangled output modes refer to the entangled photons with a specific frequency (e.g., the emission frequency). This unique behavior is theoretically discussed and the results show that using the lattice plasmon can change the transition rates by which the two emitted modes become entangled.
Citation - Scopus: 16
Real-Time Encryption/Decryption Algorithm With a Fractional Chaotic System of Various Data: Image, Speech, and Text
(Springer, 2022) Güler, H.; Ataş, M.T.
Nowadays, a fractional-order chaotic system is commonly used in digital cryptosystem applications due to its precision to initial conditions and their unpredictability. This paper proposed an encryption-decryption of image, sound, and text data based on fractional-order Rössler chaotic system. Firstly Master–Slave synchronization of fractional-order Rössler chaotic system designed with Labview to able to realize the encryption-decryption process. Fractional order Rössler system Master–Slave equations created to able to perform synchronization and then fractional-order Rössler chaotic system based Master–Slave design used in the image, sound, and text encryption-decryption separately. Image, sound, and text encryption-decryption process successfully realized. Original encrypted and decrypted data compared with each other respectively. © 2022, The Author(s), under exclusive licence to Springer Nature India Private Limited.

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