Yazar "Koyuncu, Ismail" seçeneğine göre listele

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    Design and Implementation of Chaos Based True Random Number Generator on FPGA
    (Ieee, 2014) Koyuncu, Ismail; Ozcerit, Ahmet Turan; Pehlivan, Ihsan; Avaroglu, Erdinc
    Currently, chaotic signal generators is of importance in cryptographic applications and chaotic communication systems. One of the significant field of the chaotic signal oscillators are random number generators. In this paper, an FPGA-based new true random number generator system using discrete-time chaotic signal generator is presented. The system designed incorporates the Sprott 94 G chaotic system based on an FPGA deployed with IEEE 754 standard. In order to produce random bits a quantification process has been performed on the results produced by the chaotic oscillator unit. Furthermore, the XOR method has been determined as restoring function to obtain a true random bit generator. The maximum operating frequency of FPGA-based true random number generator has been able to reach up to 399,383 MHz. The 20,000-bit sequence has been generated by the designed system and they have been saved to the test result file. They have been tested using NIST test suite and FIPS-140-1 standards and successful results have been obtained. It is concluded that the FPGA-based system is able to be used in cryptologic applications.
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    Hybrid pseudo-random number generator for cryptographic systems
    (Springer, 2015) Avaroglu, Erdinc; Koyuncu, Ismail; Ozer, A. Bedri; Turk, Mustafa
    For a powerful cryptographic system, high-quality random number streams are essential. Those raw pseudo-random number generators (PRNG) that are used to generate high-quality random numbers have some disadvantages, such as failure to meet the R4 security requirement. Therefore, use of random number sequences generated by these generators in a cryptographic system puts the entire system at risk. This study proposes a new hybrid PRNG by means of an additional input introduced to transition and output functions used in a raw PRNG system in order to eliminate this risk. The additional inputs to the designed system have been implemented via the true random number generator developed by using the Sprott 94 G chaotic system on FPGA. The random number streams obtained from the recommended hybrid structure have been subjected to the NIST 800.22 and FIPS statistical test, which have given good results. According to these results, it has been proved that the recommended hybrid PRNG system meets the R4 security requirement and can be used in cryptographic applications.
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    Investıgation of thiol-dısulfıde balance ın chıldren wıth pneumonıa
    (2020) Solmaz, Abdullah; Cevirgen, Busra; Koyuncu, Ismail; Guzelcicek, Ahmet
    Aim: We aimed to investigate the thiol-disulfide balance, role of oxidative stress in pneumonia and role of measurement of thiol as a new biological marker for the diagnosis of pneumonia in children with pneumonia who admitted to pediatric emergency service and general pediatric polyclinic.Material and Methods: In our study, patients between 6 months and 4 years of age, who admitted to the Pediatric Emergency Department and Pediatric Policlinic of between January 2017 and February 2018 with a diagnosis of community-acquired pneumonia, were evaluated prospectively. A total of 90 patients were included in the study, including 45 patients and 45 healthy children in the same age group. These patients were examined for age, gender, symptoms and physical examination findings, native thiol, total thiol and disulfide values. Results: There was no significant difference between the patient and control groups in terms of gender. Statistically significant difference was observed between native thiol, total thiol and disulfide values between patient and control group (p0.05). In the patient group, the levels of native thiol and total thiol were low and disulfide levels were found to be high. There was a significant difference between patient and control group in terms of disulfide / total thiol, disulfide / native thiol and native thiol / total thiol parameters (p0.05). Disulfide / total thiol and disulfide / native thiol parameters were high in the patient group. Nativethiol / total thiol ratio was found to be high in the control group. Conclusion: In children with pneumonia; native thiol, total thiol, disulfide and their ratios were found to be significantly correlated. It was found that oxidative stress has an important role in the pathogenesis of pneumonia. The use of thiols in the diagnosis of pneumonia may guide clinicians.