Design and implementation of robust embedded processor for cryptographic applications

Practical implementations of cryptographic algorithms are vulnerable to side-channel analysis and fault attacks. Thus, some masking and fault detection algorithms must be incorporated into these implementations. These additions further increase the complexity of the cryptographic devices which already need to perform computationally-intensive operations. Therefore, the general-purpose processors are usually supported by coprocessors/hardware accelerators to protect as well as to accelerate cryptographic applications. Using a configurable processor is just another solution. This work designs and implements robust execution units as an extension to a configurable processor, which detect the data faults (adversarial or otherwise) while performing the arithmetic operations. Assuming a capable adversary who can injects faults to the cryptographic computation with high precision, a nonlinear error detection code with high error detection capability is used. The designed units are tightly integrated to the datapath of the configurable processor using its tool chain. For different configurations, we report the increase in the space and time complexities of the configurable processor. Also, we present performance evaluations of the software implementations using the robust execution units. Implementation results show that it is feasible to implement robust arithmetic units with relatively low overhead in an embedded processor

Assessment of aerodynamic response of the Nissibi cable-stayed bridge using three-dimensional computational fluid dynamics

Aerodynamic behavior has the greatest impact on long-span bridges and is the most important factor in the design of cable stayed bridges, which should not be overlooked. CFD (Computational Fluid Dynamics) is the most widely used technique, among bridge engineers, to predict wind speed, direction and vortex-shedding form before conducting wind tunnel tests. In this study, a bi-directional CFD analysis with the wind flow parallel and perpendicular to Nissibi Bridge's, which has a main span of 400 m and claimed the spot of Turkey’s 3rd largest bridge, deck cross-section has been performed by approximate modelling of the bridge and the surrounding structures. The study is done by using CFD++ software/computer program. The results showed that the effect of wind acting on x direction of impact with 30 m/s has caused turbulence and vortex on conjugation area of the tower and it is observed that the upside down Y shape of the tower breaks down the balance of wind flow. However, bridge deck is not exposed to serious amount of vortex influence due to the wind on y direction. In addition, the analysis revealed that maximum pressure distribution occurred on vertical surface of the tower and it increases in direct proportion to the height of the tower

The influence of different concrete classes on the seismic response of a seismically isolated building

In this study, an eight story seismically isolated building representing a mid-rise type building was employed to investigate the effect of usage of different concrete classes (C20, C25, C30, C40, and C50) on the seismic response of a seismically isolated building. The prototype fixed base buildings were converted to seismically isolated buildings by introducing rubber isolators at base level. Analyses were conducted by using two different isolation systems (QW5Tb3 and QW10Tb3).The modelling of conventional fixed base prototype seismically isolated buildings and their modal analyses were conducted on finite-element program SAP2000, whereas, modelling of seismically isolated buildings and nonlinear time-history analyses were conducted using 3D-BASIS program. Floor accelerations, Story shears and inter-story drift ratios were the key structural responses considered. The analysis results showed concrete strength have significant effects on the seismic behaviour of the structures. Seismically isolated buildings with isolation system having 5% characteristic strength, C40 and C50 concrete buildings showed less first floor accelerations as compared to the lower concrete class buildings. In addition, isolated buildings with C40 and C50 concrete showed much more inter-story drift ratio values at each floor level as compared to isolated buildings with C20, C25 and C30 concrete which showed values very close to one another

Covid-19 Pandemisinin ve Uzaktan Eğitimin Mesleki ve Teknik Anadolu Liselerinde Öğrenci Başarılarına Etkisinin İncelenmesi

2019 yılında Çin’in Wuhan kentinde ortaya çıkan ve hızla tüm dünyaya yayılan Koronavirüs (Covid-19) pandemisi ile birlikte, yakın geçmişte hayal bile edilemeyecek seviyede deneyimler küresel anlamda hayatımıza girmiştir. Hayatın her alanını derinden etkileyen Covid-19 virüsü tüm sektörleri olduğu gibi eğitime yönelik bakış açısını da yeniden değerlendirmeyi gerekli kılmıştır. Öyle ki; salgının tüm dünyada ciddi sağlık sorunları oluşturması ve yüksek ölüm oranlarına ulaşılması ile eğitim öğretim faaliyetlerinde normal düzenin dışına çıkılması ve alternatif çözümlerle yeni, hızlı bir düzen oluşturulması gündeme gelmiştir. Sosyal izolasyonu sağlamak amacıyla alınan karantina önlemleriyle, zorunlu olarak devreye sokulan uzaktan eğitim faaliyetleri, tüm dünyada olduğu gibi Türkiye’de de pandemi sürecinin getirdiği eğitsel olumsuzluklara başlangıçta hızlı ve olumlu bir cevap vermiştir. Araştırmada zorunlu uzaktan eğitimin olumlu ve olumsuz yönleri ve uzaktan eğitimin yüz yüze eğitime karşı başarıya katkısı istatistiki verilerle tespit edilmeye çalışılmıştır. Çalışmanın amacı; korona virüs salgını nedeniyle uzaktan eğitime hızlı bir geçiş yapan ve eğitim sisteminin önemli bir parçası olan mesleki ve teknik eğitimde yaşanan olumlu ve olumsuz yönleri belirlemek, mesleki ve teknik Anadolu liselerinde teorik ve uygulamalı eğitimde yaşanan aksaklıkları değerlendirerek yıl sonu öğrenci başarılarını irdelemektir. Araştırmada 413 öğrencinin son dört yıllık not ortalamalarındaki değişim test edilmiştir. Kadın öğrencilerin pandemi sürecinin başlangıcında erkek öğrencilerle denk olan başarı ortalamalarının son üç yılda kadınlar lehine yükseldiği anlaşılmıştır. Aynı kampüste bulunan okulların başarı ortal

Köprülerin Deprem Etkileri Altındaki Davranışları

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017Depremlerde köprü, viyadük ve benzeri yapıların hasar görebildiği ve hatta yıkılabildiği bilinmekle birlikte; nedenleri henüz kesin olarak belirlenememiştir. Deprem etkisine maruz köprü türü yapıların davranışları araştırılırken, mevcut araştırmalarda genellikle sadece yatay etkilerin hesaba katıldığı görülmektedir. Hatta günümüze kadar süregelmiş önemli uluslararası şartnamelerde de yalnızca yatay etki hesaba katılmaktadır. Yalnızca yatay etkilerin hesaba katılmasında önemli nedenlerden bir tanesi, düşey yüklerin deprem esnasında meydana gelebilen olası çekme kuvvetlerine kıyasla küçük olması durumunda sistemin mekanizma haline gelmesi (oynak olması) ve sonuçta çözümün pratik olarak imkânsız hale gelmesidir. Bu durumda problem çözülememekte ve düşey etkiler hesaba katılamamaktadır. Mevcut çalışmada yapısal sistemlerin alışılagelmiş deprem analizlerinin yanı sıra düşey etkiler de hesaba katılmaktadır. Çalışmanın bu aşamasında yapısal elemanlar arasında göçme mekanizmaları belirlenebilmektedir. Konu ile ilgili çalışmaların yıllarca devam edeceği ön görülmekte ve devamında tüm yapısal sistemlerde (bina, baraj, köprü, viyadük vb.) düşey deplasman etkisinin göz önüne alınmasının kaçınılmaz olduğu sonucunun bulunmasının kuvvetle muhtemel olduğu düşünülmektedir. Bu durumda tüm analiz yöntemleri ve şartnameler gözden geçirilmelidir.It is known that bridges, viaducts and similar structures may be damaged and even destroyed under earthquake excitation; however, exact causes have not been determined yet. While the behavior of bridge-type structures subjected to earthquakes is being investigated; it is observed that, generally, only horizontal effects are included in the current studies. Furthermore, only the horizontal impact is taken into account by important prevailing international specifications/codes. One of the main reasons for inclusion of only horizontal effects in the calculation is the possibility for the system to become mechanism if the vertical loads are small compared to the probable tension forces during the earthquake, ultimately, causing the solution to become practically impossible. Because of this, the problem cannot be solved and the vertical effects cannot be taken into account. In the present study, besides the conventional earthquake analyses of structures with lateral forces, the vertical effects are also taken into account. At this stage of the study, the mechanisms of collapsing can be determined for the structural elements. It is anticipated that studies on the subject will continue for many years, and it is highly likely that the consideration of the vertical displacement effect would become inevitable for all types of structures (building, dam, bridge, viaduct etc.). In this case, all analysis methods and specifications should be reviewed

Vitamin D Düzeyinin İnvaziv Elektrofizyolojik Parametrelere ve Atriyal Fibrilasyon İndüklenebilirliği’ne Etkisi

Deficiencies of Vitamin D (VitD) has been associated with coronary heart disease, hypertension and left ventricular hypertropy. However its effects on cardiac conduction system and atrial fibrillation (AF) predisposition have not been studied yet. In this study we aim to evaluate the effects of VitD on invasive electrophysiologic parameters and AF inducibility. Materials and Methods: This retrospective crosssectional study included 135 patients. Study population was divided into three group as VitD sufficient, VitD insufficient and VitD deficient according to baseline vitD levels. Patients’ invasive electrophysiologic parameters and induced AF episodes were recorded. Results: Corrected sinus node recovery time, baseline cycle length, atrial-His interval, His-ventricular interval and Wenckebach cycle length were lengthened in vitD deficient group but they didn’t reach statistical significance. The rate of AF inducibility was twice as likely in VitD deficient group than sufficient group, however, it also didn’t reach statistical significance. Conclusion: Baseline VitD levels were not associated with cardiac electrophysiologic parameters and AF inducibility. To demonstrate the role of VitD in cardiac conduction system and AF inducibility thoroughly, further studies such as addressing VitD replacement are warranted.Amaç: Vitamin D (vit D) eksikliği, koroner kalp hastalığı, hipertansiyon ve sol ventrikül hipertrofisi ile ilişkili bulunmuştur. Ancak kardiyak iletim sistemi ve atriyal fibrilasyon (AF) yatkınlığına etkisi henüz araştırılmamıştır. Bu çalışmada, VitD'nin invaziv elektrofizyolojik parametreler ve AF indüklenebilirliği üzerindeki etkilerini değerlendirmeyi amaçladık. Gereç ve Yöntem: Bu retrospektif kesitsel çalışma 135 hastayı içermektedir. Çalışma popülasyonu, temel vitD düzeylerine göre VitD yeterli, VitD yetersiz ve VitD eksikliği olmak üzere üç gruba ayrıldı. Hastaların invaziv elektrofizyolojik parametreleri ve uyarılan AF epizodları kaydedildi. Bulgular: Düzeltilmiş sinüs nodu iyileşme zamanı, bazal döngü uzunluğu, atriyal-His aralığı, His-ventriküler aralık ve Wenckebach siklus uzunluğu, vitD eksikliği olan grupta uzamış, ancak istatistiksel olarak anlamlı bulunmamıştır. AF indüklenebilirlik oranı, VitD eksikliği olan grupta, yeterli gruba göre iki kat daha fazlaydı., ancak istatistiksel olarak anlamlı değildi. Sonuç: Bazal VitD seviyeleri kardiyak elektrofizyolojik parametreler ve AF indüklenebilirliği ile ilişkili değildi. VitD'nin kardiyak iletim sistemindeki rolünü ve AF'nin indüklenebilirliğini tam olarak göstermek için VitD replasmanını da içeren daha ileri çalışmalar gereklidir

Investigation of survivin gene polymorphism in patients with gastric carcinoma

Objectives: Despite decreasing incidence of gastric cancerin worldwide, it is still a major health problem. Everyyear, 30.000 new gastric cancer cases emerging, and itis the second most common cancer in Turkey. Gastriccancer is a complex multifactorial disease, emerging byinteraction between genetic and environmental factors.Survivin, apoptosis inhibitory protein is over-expressed incancer tissue. In this study, association between Survivin-31G/C polymorphism and gastric carcinoma was investigated.Materials and Methods: 46 gastric carcinoma patientswho had been admitted at Düzce University Researchand Practice Hospital, Laboratory of Pathology and 42healthy individuals have been included in the study. Sampleshave been subjected to genetic analysis by PCRRFLPmethod in Medical Genetics Department laboratoryat Düzce University.Results: GG genotype was found in 16 (34.8%), GCgenotype in 21 (45.7%), CC genotype in 9 (19.6%) in patientgroup. In control group, genotype distribution werefound 13 (31%), 26 (61.9%) and 3 (7.1%) respectively.The statistically significant difference was not found whencompared between patient and control groups. However,we observed the increased occurrence of gastric cancerassociated with CC genotype (OR=1.52).Conclusions: In our knowledge, this study is the first toevaluate the relationship between gastric carcinoma andSurvivin -31G/C polymorphism in Turkish population. Ourresults show that there is no any association betweengastric carcinoma and Survivin -31G/C polymorphismin the community which is represented by our study andcontrol groups. However, it was concluded that CC genotypemay create the susceptibility to gastric cancer.Key words: Polymorphism, gastric carcinoma, survivinggene, apoptosi

Soft-story effects on the behaviour of seismically isolated buildings under near and far-fault earthquakes

In this study, the effects of soft-story on the seismic behaviour of 3-story and 8-story isolated buildings under near and far-fault earthquakes were investigated. Four different structural models with two different 1st story height were designed: One with 1st story height of 3m and 2nd with 1st story height of 4.5m to capture soft story effect. The prototype fixed base buildings were converted to seismically isolated buildings by introducing rubber isolators at base level. Analyses were conducted by using two different isolation systems (QW7.5Tb3 and QW7.5Tb4). The modelling of conventional fixed base prototype seismically isolated buildings and their modal analyses were conducted on finite-element program SAP2000, whereas, modelling of seismically isolated buildings and nonlinear time-history analyses were conducted using 3D-BASIS program. The four accelerations records has been used for the time-history analysis. Floor accelerations, story shears and inter-story drift ratios were the key structural responses considered. The analysis results showed seismic isolations can be used as a viable mitigation method for the buildings with soft-stories under near and far-fault earthquakes. Based on the results obtained, it is interesting to note that all types of buildings whether with soft story or with typical story height show the same acceleration trend and close values (except top floor) for all types of isolation systems and earthquakes considered. In addition, both 3 and 8-story buildings suffered increase in interstory drifts beyond the limits defined UBC 97 under earthquakes containing long period pulses