Kriptolojik uygulamalar için FPGA tabanlı yeni kaotik osilatörlerin ve gerçek rasgele sayı üreteçlerinin tasarımı ve gerçeklenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu tez çalışmasında, gerçek zamanlı, yüksek çalışma frekansı ve bit üretim hızına sahip Gerçek Rasgele Sayı Üreteçleri (GRSÜ), FPGA tabanlı kaotik osilatörler kullanılarak tasarlanmış ve gerçekleştirilmiştir. Bu amaçla tezin ilk aşamasında, çeşitli sistem parametrelerinin karşılaştırılması ve değerlendirilmesi amacıyla iki farklı kaotik sistem dört farklı nümerik diferansiyel denklem çözüm metodu ile modellenerek sistemlerin dinamik davranışları incelenmiş ve kaos analizleri yapılmıştır. İkinci aşamada, seçilen kaotik sistemler bir ECAD programında şematik giriş yapılarak analog devre elemanları ile modellenmiştir. Nümerik benzetim sonuçları ile ECAD benzetim sonuçları karşılaştırılmıştır. Elde edilen sonuçlara göre analog elemanlar kullanılarak yapılan ECAD benzetimi ile Matlab destekli nümerik model sonuçları birbiri ile uyumlu değerler üretmiştir. Sonraki aşamada, kaotik sistemler dört farklı diferansiyel denklem çözüm metotlarından yararlanılarak, 32-bit IEEE 754-1985 kayan noktalı sayı standardında VHDL programlama dili ile FPGA üzerinde modellenmiştir. Tasarımlar Virtex–6 ailesi XC6VLX550T-2FF1759 çipi için Xilinx ISE Design Tools 14.2 benzetim programı kullanılarak sentezlenmiştir. Elde edilen sonuçlara göre FPGA-tabanlı kaotik osilatörlerin maksimum çalışma frekansları yaklaşık olarak 390-464 MHz arasında değişmektedir. Buna göre kaotik osilatör ünitesi 1 milyon veriyi 46 ms gibi çok kısa bir sürede hesaplayabilmektedir. Bu aşamada, FPGA tabanlı ünitelerin ürettiği sonuçların doğruluğunu test etmek amacıyla RMSE yöntemi kullanılarak hassasiyet analizleri de yapılmıştır. Dördüncü aşamada, FPGA-tabanlı örnek kaotik sistemler kullanılarak GRSÜ tasarımı gerçekleştirilmiştir. Genel olarak iki farklı kaotik sistem, kaotik osilatör tasarımında dört ayrı algoritma ve kuantalama için üç değişik yöntem sunularak toplamda 24 farklı gerçek rasgele sayı üreteci ünitesi tasarlanmıştır. Tasarımlardan elde edilen sonuçlara göre, ünitelerin maksimum çalışma frekansları 339-401 MHz ve bit üretim hızları 53-132 Mbit/s arasında değişmektedir. Son aşamada, FPGA tabanlı GRSÜ'den elde edilen sayı dizileri FIPS-140-1 ve NIST-800-22 istatistiksel rasgelelik testleri kullanılarak test edilmiş ve tüm testlerden başarılı olmuştur.In this thesis, real-time True Random Number Generators (TRNGs) with high operating frequency and bit generation rate have been designed and implemented using FPGA-based chaotic oscillators. In the first stage, two separate chaotic systems have been determined and their dynamical behavioral and chaotic analysis have been investigated to compare various system parameters using by four diverse numerical differential equation solution methods. In the second stage, the chaotic systems have been modelled using analog components in an ECAD program. After that numerical and ECAD simulation results have been compared and the results obtained from each simulation proves that both approaches have produced compatible outcomes. In the next stage, the chaotic systems have been modelled in VHDL in 32-bit IEEE 754-1985 floating point number standard using by four diverse numerical differential equation solution methods. The designs have been synthesized for Virtex–6 using Xilinx ISE Design Tools 14.2. According to the syntheses results, the maximum operating frequency of the FPGA-based chaotic oscillators varies between 390 MHz and 464 MHz. Accordingly, the chaotic oscillator unit has been able to calculate 1 million data sets in 46 ms. In this stage, in order to test accuracy of results produced by FPGA-based units, the sensitivity analysis have been also performed by employing RMSE method. In the fourth stage, TRNG designs have been implemented using FPGA-based chaotic systems. 24 different TRNG units have been designed and implemented by employing two distinct chaotic systems, four different algorithms in the design of the chaotic oscillators and three diverse quantification methods. According to the results, operating frequency of the units varies between 339 MHz and 401 MHz and the bit-rates varies between 53 Mbit/s and 132 Mbit/s

Self forming dynamic membrane filtration for drinking water treatment

Lab-scale continuous operation of self forming MF and UF dynamic membranes were investigated simultaneously by applying iron oxide as an alternative treatment option in those waters having natural organic matter (NOM), iron and manganese. Both dynamic membranes gave high removal rates and effluent concentrations of pollutants were below the limit values in synthetic water. 60-62% of DOC and 75-78% of UV254 were removed in low DOC synthetic water (LS) by MF and UF dynamic membranes, respectively. Although only 42-49% of DOC and 48-53% of UV254 could be removed by MF and UF dynamic membranes, remarkable effect on fouling alleviation was observed in high DOC synthetic water (HS). Iron oxide did not enhance the removal of organic matter in low DOC natural water (LN) as much as it did in synthetic water. Iron oxide led to the removal of high molecular weight organics, thus reversible fouling reduced almost 2 orders of magnitude through both types of dynamic membranes in high DOC natural water (HN). Reversible and ireversibe resistances were reduced by iron oxide to some extent in LN. Nevertheless the effect of iron oxide on fouling alleviation was much higher in HN than LN.Scientific Research Projects Coordination Unit of Istanbul University-Cerrahpasa [2810]; Memtek National Research Center on Membrane TechnologiesThis work was supported by Scientific Research Projects Coordination Unit of Istanbul University-Cerrahpasa. Project number:2810. The authors appreciate the support and cooperation of Memtek National Research Center on Membrane Technologies during this research study

Exposure of emergency nurses to workplace violence and their coping strategies: A cross-sectional design

Introduction: Violence against nurses working in the emer-gency department is a serious problem worldwide.Methods: This descriptive study used a participant question-naire and was conducted in-person, using semi-structured inter-views with 120 emergency nurses (69 female, 51 male) working in the emergency department between September 1 and November 30, 2017.Results: Overall, 90% of the study participants were exposed to workplace violence at least once while working in the emer-gency department, and 94.4% experienced verbal abuse, including insults, shouting, threats, and swearing. Most of such workplace violence came from the patients relatives. Most workplace violence incidents occurred during the 4 PM to midnight time slot and in the triage area. The most important perceived reasons for workplace violence were the long waiting period for treatment and care (79.6%) and not being prioritized for treatment (68.5%). The top 3 coping methods used were reporting to the nurse in charge (78.1%), followed by reaching out to the security personnel (72.8%) and filing lawsuits if exposed to physical violence (65.8%).Conclusions: Most emergency nurses had experienced work -place violence. Hospital administration should take more effec-tive security measures, hospitals should provide education and training programs for dealing with workplace violence, and pro-grams to support staff members on encountering workplace violence should be implemented

Natural Organic Matter Removal and Fouling in a Low Pressure Hybrid Membrane Systems

The objective of this study was to investigate powdered activated carbon (PAC) contribution to natural organic matter (NOM) removal by a submerged MF and UF hybrid systems. It was found that filtration of surface waters by a bare MF and UF membranes removed negligible TOC; by contrast, significant amounts of TOC were removed when daily added PAC particles were predeposited on the membrane surfaces. These results support the assumption that the membranes surface properties and PAC layer structure might have considerably influential factor on NOM removal. Moreover, it was concluded that the dominant removal mechanism of hybrid membrane system is adsorption of NOM within PAC layer rather than size exclusion of NOM by both of membrane pores. Transmembrane pressure (TMP) increases with PAC membrane systems support the view that PAC adsorption pretreatment will not prevent the development of membrane pressure; on the contrary, PAC particles themselves caused membrane fouling by blocking the entrance of pores of MF and UF membranes. Although all three source waters have similar HPI content, it appears that the PAC interaction with the entrance of membrane pores was responsible for offsetting the NOM fractional effects on membrane fouling for these source waters

Forward Osmosis Membranes – A Review: Part II

Forward osmosis (FO) is a technical term describing the natural phenomenon of osmosis: the transport of water molecules across a semipermeable membrane by osmotic pressure from a feed solution (FS) to a draw solution (DS). The diluted DS is then reconcentrated to recycle the draw solutes as well as to produce purified water. As the driving force is only the osmotic pressure difference between two solutions, meaning that there is no need to apply an external energy, this results in low fouling propensity of membrane and minimization of irreversible cake forming, which are the main problems controverted by membrane applications, especially in biological treatment systems (e.g., FO membrane bioreactor (FO-MBR)). The purpose of the book chapter is to bring an overview on the FO membrane manufacturing, characterizing and application area at laboratory or full scales. This book chapter is published in two parts. In the second part, which appears here, characterization of mass transport in FO membranes, fouling mechanisms and foulants on FO membranes in naturally asymmetric structure and application areas of FO membranes in the literature are mentioned. Cutting-edge technologies on FO studies are comprehensively reviewed and following major and minor titles are stated truly on the new technologies

Comparative Impact of SiO2 and TiO2 Nanofillers on the Performance of Thin Film Nanocomposite Membranes

Nanoparticle (NP) additions can substantially improve the performance of reverse osmosis and nanofiltration polyamide (PA) membranes. However, the relative impacts of leading additives are poorly understood. In this study, we compare the effects of TiO2 and SiO2 NPs as nanofillers in PA membranes with respect to permeate flux and the rejection of organic matter (OM) and salts. Thin‐film nanocomposite (TFN) PA membranes were fabricated using similarly sized TiO2 15 nm and SiO2 (10 – 20 nm) NPs, introduced at four different NP concentrations (0.01, 0.05, 0.2, and 0.5% w/v). Compared with PA membranes fabricated without NPs, membranes fabricated with nanofillers improved membranes hydrophilicity, membrane porosity, and consequently the permeability. Permeability was increased by 24 and 58% with the addition of TiO2 and SiO2, respectively. Rejection performance and fouling behavior of the membranes were examined with salt (MgSO4 and NaCl) and OM (humic acid [HA] and tannic acid [TA]). The addition of TiO2 and SiO2 nanofillers to the PA membranes improved the permeability of these membranes and also increased the rejection of MgSO4, especially for TiO2 membranes. The addition of TiO2 and SiO2 to the membranes exhibited a higher flux and lower flux decline ratio than the control membrane in OM solution filtration. TFN membranes\u27 HA and TA rejections were at least 77 and 71%, respectively. The surface change properties of NPs appear to play a dominant role in determining their effects as nanofillers in the composite membrane matrix through a balance of changes produced in membrane pore size and membrane hydrophilicity

Evaluation of oxidative stress in degenerative rotator cuff tears

Background: Oxidative stress occurs as a result of the disruption of the balance between the formations of reactive oxygen species and antioxidant defense mechanisms during the conversion of nutrients into energy. Increased body oxidative stress has been reported to be involved in the etiology of several degenerative and chronic diseases. We hypothesized that the body oxidative stress level is higher in patients with atraumatic degenerative rotator cuff tear than that in healthy individuals. Methods: The patients who underwent arthroscopic repair for atraumatic, degenerative rotator cuff tear were prospectively evaluated. A total of 30 patients (group 1, 19 females and 11 males; mean age: 57.33 ± 6.96 years; range: 50-77 years) and 30 healthy individuals (group 2, 18 females and 12 males; mean age: 56.77 ± 6 years; range: 51-72 years) were included in the study. The Constant and American Shoulder and Elbow Surgeons scoring systems were used to evaluate the clinical outcomes. Serum oxidative stress parameters of the patients and the control group were biochemically evaluated. Accordingly, thiol/disulfide (DS) balance (DS/native thiol [NT], DS/total thiol [TT]), Total Oxidant Status (TOS), oxidative stress index, and nuclear factor erythroid-2–associated factor-2 values were used as the biochemical parameters indicating an increase in the serum oxidative stress level. Total antioxidant status and NT/TT values served as the biochemical parameters indicating a decrease in the serum oxidative stress level. Results: The study follow-up duration was 12 months. A statistically significant increase was observed in American Shoulder and Elbow Surgeons and Constant scores of patients who underwent arthroscopic rotator cuff repair relative to that during the preoperative period (P = .01). The values of biochemical parameters (DS/NT, DS/TT, TOS, oxidative stress index, and nuclear factor erythroid-2–associated factor-2), which indicated an increase in the serum oxidative stress, were significantly higher in preoperative patients than those in postoperative patients, albeit the control group values were significantly lower than those of the postoperative patients. The biochemical parameters (NT/TT and total antioxidant status) indicating a decrease in the serum oxidative stress levels were significantly higher in the postoperative patients than those in the preoperative patients and significantly lower than those in the control group. Conclusion: High levels of markers indicating an increase in the serum oxidative stress in patients with degenerative rotator cuff rupture suggested that TOS may be involved in the etiopathogenesis of rotator cuff degeneration. Although the oxidative load decreases during the postoperative period, the fact that it is still higher than that in healthy individuals supports this claim. © 2022 Journal of Shoulder and Elbow Surgery Board of Trustee

Investigation of pilot scale manufacturing of polysulfone (PSf) membranes by wet phase inversion method

Membranes are used as a support layer for the fabrication of thin film composite membranes. Sup- port layer properties can affect many performance parameters of TFC membranes such as flux, rejection, morphology and stability against pressure. Although studies in lab scale fabrication exist, investigation the pilot scale polysulfone membrane fabrication has not been done. In this study, opti- mization of polysulfone support membranes fabrication was conducted in pilot scale. Coagulation bath temperature; casting speed and solution content were selected as main parameters for the opti- mization. Membrane surface properties were investigated in details with SEM and pore size dis- tribution. Membrane performance were determined with permeability experiments. Differences in pilot scale and lab scale membrane manufacturing were observed and compared with literature. On the contrary to literature it was found that, coagulation bath temperature has exact opposite effect in pilot scale membrane formation compared to lab scale studies. 10°C drop (from 25°C to 15°C) in coagulation bath temperature decreased mean pore size of membranes from 27 nm to 8 nm and per- meability from 464 l/m2h to 100 l/m2h while everything else was kept constant

Nuclear Factor Erythroid 2-Related Factor (NRF2), Heme Oxygenase 1 (HO-1) and Total Oxidant-Antioxidant Status in Patients with COVID-19

Introduction: Studies on nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) levels in COVID-19 patients are limited. This study aimed to investigate the relationship between some biomarkers of oxidant-antioxidant status with COVID-19 disease. Material and methods: The patients older than 18 years of age who tested positive for SARS CoV-2 PCR (polymerase chain reaction) with clinical symptoms and signs were included in this study. Total antioxidant status (TAS), total antioxidant status (TOS), oxidative stress index (OSI) and HO-1 and Nrf2 levels were analyzed from serum samples taken before and after treatment. Results: In this study, 16 patients followed up with the diagnosis of COVID-19 were included. 9 (56.3%) of the patients were female and 7 (43.8%) were male. The mean age was 33.75 ± 17.03 years. All patients were symptomatic and were hospitalized to be followed up. It was determined that Nrf2 and HO-1 values increased significantly after treatment. Moreover, there was a significant positive correlation between Nrf2 and TAS values and TAS increases significantly in parallel to an increase in Nrf2, and there was a significant but negative correlation between Nrf2 and TOS and OSI values, and thus an increase in Nrf2 led to a decrease in TOS and OSI values. There was a significant positive correlation between HO-1 and TAS, and TAS increased significantly, as HO-1 increased. Conclusions: The decrease in TOS and OSI and the increase in Nrf2 and HO-1 during the follow-up period in COVID-19 patients suggest that the body tries to prevent ROS-related oxidative stress via Nrf2 and HO-1 and that oxidative stress may have a key role in the pathophysiology of COVID-19